I'm a working professional videographer, but no i don't put the same expectations on a camera like the hero4 that i do on my other bigger cameras. Up until now I've been using a hero 3 black for both professional and personal uses. Considering my satisfaction with the hero3, picking up a hero4 was inevitable

**UPDATE: Took off a star for questionable issue: While i haven't come across any major glitches, it does seem to hiccup here and there (my hero3 did the same), the heat that comes off it can be more than warm, but it seems others are experiencing rather hot temperatures. While not entirely reassuring, i've heard some folks have positive experiences dealing with gopro on their overheating matters. We'll have to wait and see, so be sure to buy from a reputable dealer!

What i like about the hero 4 black:

-4K at usable framerates (hero3 could only do 15fps)
-Sweet 120fps slow motion at 1080
-More wireless connectivity(some hiccups, but can work)
-More slowmotion
-Sharpness is satisfactory
-Lowlight is decent enough
-More manual control

What's not to like?

-Battery still not great
-No rear touchscreen
-Doesn't make bacon pancakes
-Doesn't banish ISIS members to the phantom zone(that place jor-el banished general zod to)

New manual controls:

Finally, you can make exposure adjustments! For instance: for night timelapses, you usually want longer exposure times/shutter speed, and you can now do it with this little cam. I need to play with this more to see how well it really performs

No screen:

Many people are very confused as to why the silver edition has it but the black does not. Yea, it's odd and i would have much preferred the flagship get the screen, that being said, i've gotten along very well with my screen-less hero 3, because i have a cautious understanding of the angles it can capture at narrow/medium/wide settings. I'll usually use it as a backup/bonus angle that i don't plan to rely on.That, and it has the phone app in case i need to verify i'm getting the angle i need. The new hero4 has even more connectivity and despite the lack of a screen, as long as you have some digital device with you, it can likely connect and give you a live view.

My bottom line about the screen? You can always add a screen to the black, you cannot add the black features to the silver. The wifi connectivity suits me fine for framing.

Size/weight:

Not much change! That's a good thing, still works with most of all the accessories/etc

Battery life:

Seems nothing improved over the hero3, still under an hour per charge. Wasabi has a decent extended battery for the hero3, grab that up once they make it for the hero4.

Heat

Possible concern: Can get very warm depending on the settings, and i've seen some users experience very hot temperatures. we'll have to see if this becomes a widespread thing, considering the hero's size, you can't imagine much heat dissipation designed into there. My main concern is the longevity of the device given the heat. heat wears electronics down, reducing their life, if this thing's average temperature is 130degrees, how long will it live? Might be a valid concern, but can't tell without real long testing.

Resolution and Framerates:

Of course the big headline feature is 4k, and that's probably what you're going to buy this thing mainly for. 4k allows for lots of reframing in editing if you're still planning on outputting to 1080. The 4k from the hero4 looks pretty satisfying, maybe not as sharp as bigger/professional cameras, but this is a tiny actioncamera, and i don't see it reasonable to hold it to quite the same standards. for a $500 pocket camera, it's plenty good.

Slow motion keeps getting better on the gopros, there's not much else to say except that you're now getting 1080 at 120fps. Something rare in a camera in this price range, my rx10 which is around a grand can only do 120fps at 720.

Bitrate:

4k gives you up to 60mpbs, which may sound low, but other more expensive cameras use a similar setup and get nice results, and the gopro does pretty well here as well. THe main area where you can see breakup in the codec is fast motion throughout the entire frame, but since all the angles are wide, and many of the details small, the breakup is pretty well controlled. Not perfect, but IMO plenty acceptable for this tiny camera.

Summary, competitors:

If you want 4k in a tiny, rugged camera, the hero4 is on a list of its own. While there are other cameras out there, the overall package gopro has with the hero4 black is impressive, and whether you're a professional or just an enthusiast, it'll get you some nice shots.

This camera is by far the most advanced gopro yet. People are complaining about the black edition not having an LCD screen and the cheaper silver version having an LCD. I'll tell you exactly why, 1) the black edition isn't for the average Joe who wants to play back what they've just shot. 2) the black edition is too powerful for an lcd screen. 4k30fps 2.7k50fps and the holy grail 1080p120fps. These are some powerful settings.

Remember this is an ACTION camera, the people using the black edition aren't worried about viewing what they're shooting at the time, they're focused on what they're doing. Also, the gopro was designed to film yourself so you wouldn't be looking at an LCD screen anyway.

As far as the app goes, It's simply to see the angle you've mounted your gopro at and to control the recording. For example, let's say you mount it on your head and you want to make sure the angle is good, connect to the app, check your angle and hit record

Hope this review helps everyone who can't decide between the black and silver.

UPDATE: 10/29/2014
So I bought the new SD Card and managed to play around with more of the settings.
The new faster memory card fixed all my SD Card errors so the only thing left keeping it from the "perfect" camera is the heating issue.
I am constantly running heat trials on this unit, mainly with the housing on and recently started opening the back housing.
Basically trying to see which recording format will allow me to record the longest duration.
The trend is anything 4K, 2.7K or above 90FPS will probably overheat in 30 mins to 1 hour. This is when the standard house, I'm sure you open the back door you can get a few more minutes, but 1 hour if you're lucky.
I manage to get the 2.7K 30FPS running 24/7 but i had to remove it entirely outside the case as I slept in my dark room.
720p30fps also manage to do 24/7 inside the case so that's good news.
So in summary any format just below 90FPS or 2.7K is probably good for about 2-3 hours. Any format at the bottom has a reasonable chance of running 24/7 or pretty long as long if you don't lay it in the sun.

Also kind of misleading is the auto low light feature is only possible in above 30FPS.

So let's be real now, the battery is only good for 1-2 hours anyways so the average Joe using the battery will find recording 1hour on 4K pretty good. Your 64gb memory card maxes out at 2hours at 4K anyways, so honestly when you compare the other limiting factors the overheating isn't as bad now
.of course you could buy spare batteries, supposedly larger yet unofficially compatible 128GB cards and now the overheating is the only problem left without a real solutionI "like" gopros official solutionjust use less features, adds 10 mins, and record smaller files aka dont use it as often lol.
I get the sense online that the overheating is to be "expected" but seriously i never hear good things in the long run about stuff constantly overheating.

I have a frame mount in the mail, so optimistic
I hope someday someone makes a battery eliminator adapter like they do for the hero 3

FINAL VERDICT.
All the features 4K, 2.7k and 80+ FPS features are cool and impressive, but don't fall in love with them because they only last 30 mins - 1 hour. It's a like a drug, once you record in 4K you don't want to go back to 1080p. I love it but i hate it too, I believe that someday they'll dial in the firmware right because I really want to like this camera. So I didn't return it.

INITIAL REVIEW:
Bought it at a local store, sorry Amazon I'm an impulse buyer and can't wait 2 days for these kind of toys.

I have a Hero 2 which I loved and expect a similar if not better experience.
This is just my initial reviews and I intend to write a full review once I iron out some bugs out.

Pros
Out of the box it is a nice sleek piece of hardware and the buttons are very friendly and responsive.
I use my Samsung S4 mini to connect via the WIFI app and overall it is a solid connection with no disconnects.
The live feed has as 1-2 second delay and I occasionally lose the feed connection, i believe it because my phone's screen times out and it interferes with the live feed connection.
Haven't tried the bluetooth yet, the option did not stand out to me as I was playing around with the App and menu screens.
Video quality is great, the 4K looks great. I'm not a video expert so I will assume the quality is legit.
Works with older generation Hero 2 LCD and extended BacPac

Cons
My biggest issues are the memory card compatibility and heating issues.
When connected to the LCD pac, it gets extremely warm.almost too hot over time. I believe this is a known bug so I stopped connecting it to the LCD.
I also notice it gets extremely warm when recording on the 4K. Which I hope is improved upon because I was planning to have this running in my car for hours in a dash cam setup. My Hero 2 never once felt warm or remotely hot.
Apparently the Hero 4 is very picky on a which SD card to use.
I used a Transcend 64GB MicroSDXC Class10 UHS-1 Memory Card with Adapter 45 MB/s that supposedly worked very well for the Hero 3+ Black.
So when I do "standard" recording with the 4K or WVGA.at the some point the Hero 4 will randomly turn off or SD error.
GoPro recently released an update that fixed this so now I can do standard recording in 4K and WVGA.
However,
When I try to do "loop" recording I always get an SD card error. No matter what format I choose, I still get an SD card error.

So normally I would be pretty frustrated, but I'm optimistic and too lazy to go back and return it for fear I received a lemon.

Instead I bought an Extreme 64 Sandisk U3, and waiting on that in the mail hoping this will fix my SD card issues.

I will gladly update my rating if the SD card works, but I would highly recommend people wait for the bugs to be ironed out before you purchase this.

The GoPro4 is a fantastic camera for the price. The faster frame rates, new features, and improved menu navigation are great. I upgraded from the GoPro 3+ Black to the GoPro4 for the faster frames per seconds at 4K, 2.7K, 1440 and 1080. But I am worried about the reliability of this new design because of the overheating of the camera in certain modes. I am an electrical engineer and know there are tradeoffs when trying to increase the performance of a system while keeping all other parameters constant. This is especially true because this new desing which has two times the processing power of its predecessor, in the same physical package, consumes more power. It's a know fact that if electronics are continually operated at temperatures above normal operating conditions, premature component failure will occur.I am certain the design team did everything possible to validate the operation and performance of the new GoPro4, but I don't think they had enough time to complete their work due to the unexpected early release of the product.

My GoPRO4 which I have used for two days, gets extremely hot, not warm which GoPRO.com claims is normal. The battery life is only around 30 to 45 if operated continuously at higher resolutions. I will probably return the GoPRO4 and purchase the GoPRO3+ Black because the price has dropped from $399 to $349 and the resolution and frame rate is suitable for my intended use.

The following is a section from the online GoPro4 user manual on the GoPro website:

High-Performance Video Modes and Camera Temperatures
The HERO4 Black features unique high-performance video modes: 4K30/24, 4K24 SuperView, 2.7K48/50, 2.7K30 SuperView, 2.7K 4:3, 1440p80, 1080p120/90, 960p120 and 720p120. When using these video modes, it is normal for the camera to become warm and use more power.
Using these high-performance modes in higher temperatures decreases camera recording time. In addition, lack of airflow around the camera, using the camera with the GoPro App, or in combination with BacPac accessories further increases camera temperature and power consumption, and decreases camera recording time.
If the camera gets too hot, a message appears on the screen indicating that the camera is shutting down. The camera stops recording, saves your video, disconnects from the GoPro App, and powers off. If this happens, let your camera sit and cool before attempting to use it again.
For extended recording time in high-performance video modes, capture shorter video clips when in stationary use, and/or limit your use of features that increase power consumption, such as the GoPro App or BacPac accessories. To control your camera remotely at higher temperatures, use the GoPro remote instead of the GoPro App.

If you're like me when I bought the 4 Black, I had three main questions:

1. Is it worth upgrading from the 3 to the 4? Short answer: mostly likely. Long answer: see below.

2. Which version of the 4 should I get? Short: Are you a pro? Black. Otherwise, the HERO or 4 Silver.

3. What else do I need? Short: a really fast microSD. Long: probably also some extra batteries

==ONE==
On upgrading - I used to own the 3+ Black. While the increased slow motion capabilities interested me, the big selling point is the 4K. In daylight, a GoPro with protune is actually surprisingly comparable to a dSLR (I do aerial cinematography for film sets). The only weak point of the 3rd generation was the softness / lack of sharpness. Now, I can film in 4k, downscale to 1080p, and it's sharper than my Canon 6D! If you have paying clients, or are seriously building your portfolio, you should upgrade. But if you already own a version of the 3, and just film things for fun.save your money for adventures :)

==TWO==
If you do decide to upgrade (or this is your first GoPro), you have three good options BESIDES the Black:

The $130 barebones HERO: http://www.amazon.com/gp/product/B00NIYNUXO/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B00NIYNUXO&linkCode=as2&tag=todmedblo-20&linkId=6RGQWHRXFRZSLFPY

The $300 HERO3+ Silver: http://www.amazon.com/gp/product/B00F3F0EIU/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B00F3F0EIU&linkCode=as2&tag=todmedblo-20&linkId=74K5GFVCEONUONTG

The $400 HERO4 Silver: http://www.amazon.com/gp/product/B00NIYJF6U/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B00NIYJF6U&linkCode=as2&tag=todmedblo-20&linkId=UMGB6UAI466WOP6K

The GoPro website has a huge spreadsheet comparing all their features but here's how I think about it:

If you're using the GoPro to just capture memories, save your money for the memories and get the HERO.

If you /think/ you're interested in using your GoPro to make more serious footage (but don't have any experience yet), pick the version of the Silver that best suites your budget. Note that the 4 Silver has a touchscreen back to help you frame your shots - that alone is worth the $100 if you can afford it.

And if you're already a heavy GoPro user (or filmmaker in general) with paying customers or past successes, get the Black. If you have a once in a lifetime trip approaching, and you have deep pockets, you might also consider the Black - but, for a lot of people, there are more meaningful things you can do with that extra money :)

==THREE==
Especially if you're filming in 4K protune, you're gonna want the fastest card you can get your hands on. I've been using this SanDisk without issue: http://www.amazon.com/gp/product/B00M55BS8G/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B00M55BS8G&linkCode=as2&tag=todmedblo-20&linkId=UVLMTWAPOPKC6RT3

It also gobbles through batteries. I seem to get about an hour of battery life, and that's only filming about half the time. Thankfully, Wasabi once again has our back with a dual battery set w/charger for just $24: http://www.amazon.com/gp/product/B00OAAUZO2/ref=as_li_tl?ie=UTF8&camp=1789&creative=390957&creativeASIN=B00OAAUZO2&linkCode=as2&tag=todmedblo-20&linkId=O67BCZ56CZ4ABYS2

I am soooo disappointed with my Hero 4 black!! I got it in the beginning of the year and since the first day strange things started happenning. I first noticed it wouldn't always respond when I pressed its buttons. Then it started freezing. The videos started coming up with strange colors like pink and green and would appear shaky. It sometimes freezes when I'm taking a photo - so it turns out completely white. Now it simply doesn't respond.
I've tried changing memory cards and the same problems continue to happen. I was using a tablet to control it and I saw that on the preview screen (without recording) the problems of striped, and wierd colors happens all the same.
I can't explain how miserable I felt after going on a boat trip (where we went diving and all..) when the camera just refused to take photos, pretended to make movies and destroying the ones that came out.
At least some photos worked!

yay??? :/

The biggest problem is that I bought it on Amazon.com but I'm not in the US anymore D:

I have had this camera for six months now, it rarely gets used anymore.

The only application I expect to keep using it for is as an underwater camera. Even for this application, the wide angle lens does not work well to take pictures of fish. You just need to get too close to them. Other point and shoot underwater cameras would have been a better choice. If you can get really close to fish, it does take good images as shown in the image I attached of the orange fish. However, most the fish end up looking small, even getting them to look as large as in the second image is difficult. For underwater photos of people, this camera is a much better choice so most people may not have the same issues.

The Gopro is useless for indoor photography. Nine photos out of ten I have taken have been blurry. That combined with the fact that the iPhone 5S produces better indoor photos means I will never use this for day to day photography. The problem is that indoors the slightest movement blurs the picture. Combined with the lack of an LCD I simply wouldn't trust this camera for something like a high school basketball game. If I did use it, it would be 30 picture bursts for everything.

I attached a typical indoor picture to demonstrate this. This was above average quality compared to others I took indoors and there was still a lot of blur.

It does take better quality video than the iPhone. Also, the fact it is waterproof and easy to mount anywhere is nice. Just realize, you are buying a very specialized device. Where it really shines is applications like surfing or rock climbing where you are outdoors and want a really tiny, easy to mount, rugged camera. If you are a typical boring American you don't have much use for this gadget.

Strongly consider whether an Olympus TG-4 would be a better choice. If you film a lot of video or mount in odd places, it may not be a good choice. However for still photos in wet environments it will blow away the Gopro. This is particularly true if you want to take macro photos.

As this was a VERY expensive purchase, let me relay my experience with the product and how the company handles issues with it.

Background:
I purchased this from Amazon (The Extreme Bundle) on May 5th, 2015. Because I needed this to work well, I made the decision to ONLY purchase GoPro branded accessories for things like Batteries and to ONLY purchase the the GoPro recommended SD Card.

Experience:
When it arrived I was pretty excited and nervous about the purchase, so I was very careful to learn all I could about how to use and care for the system. I am the kind of guy that keeps his laptop clean and dust free and is all about maintenance. Usually, this works well for me and I seldom have problems with anything that I own, unless is was defective from the factory.

I had purchased this for use at my son's final band concert as a senior in High School, and was excited to take advantage of the image and audio quality to capture everything as a memento of his senior year. It was at this point that everything started to go wrong.

During the concert it just stopped.froze up completely and would not respond. I reset it and started again.it then generated an error: SD ERR in the front LED window. I reset it again, and again received the SD ERR. I swapped out the card with another known good memory card (GoPro Recommended card) and tried again, SD ERR. I swapped the battery in the unit, just to be sureSD ERR. I adjusted the capture resolution down and tried againSD ERR!
I finally gave up and tried to capture some video with my iPhone, which workedbut was not what I wanted.

Now here is the deal, I was VERY careful about this, I purchased over $700 of GoPro brand products, because I did not want to have any problems. I read everything I could find, and watched every video about setting up and using the camera. I even watched a video about how to unbox it properly, because I really wanted to take care of this expensive equipment. To have everything go wrong like this was a total shockespecially considering the cost of the purchase.

I bought GoPro because I believed that it was a quality product and was worth the premium price. For items like this, that I MUST count on, I never go with the cheap optionbut the quality one.

Being a Microwave/Satellite comms tech, I am not stranger to troubleshooting issues. I spent the next two days troubleshooting the problem. Changing every component out, and seeing if I could identify the failure point, which was determined to be the camera. So NOW I have to send it in for service. It is the Friday before Memorial day and I have the next 4 days off with NO CAMERA!

To say that I am disappointed is an understatement of epic proportions. I will keep this live to update everyone on how my experience with support goes, but I am currently waiting for word back and am hearing NOTHING.

**********Update 5-22-2015*********
I received the information from support with instructions on how to RMA the camera back, a FEDEX label was included and I have boxed it up and prepared it for return.

My NUMBER ONE CONCERN at this point is.This was less than 2 weeks old before I began having issues. Am I going to get a refurbished camera or a new one? I say this because I considered boxing it up and returning it to Amazon for a refund, but I decided to give GoPro a chance to fix this. Because it is possible that I am just the unlucky soul who got a bad camera, and once fixed, things will be good again.

GoProI am giving you a chance! Please don't disappoint me! I don't want a refurbished camera, I want a new one. I want my wasted days back, but I am not sure how you can make that right.

*******Post replacement update*******

The replaced camera seems to be working fine, and all of my previous issues were corrected. As of 5/28, I am still up and running and I am able to use the camera as I would like. But I am concerned about all of the comments on overheating of these, so I plan on being careful with the camera and watching the temperature very closely!

I will add 1 star at this point, and see how things are going at the end of summer before I edit again and reconsider my ranking.

**Don't buy this camera, a cheap Chinese camera will perform better**

I bought this camera October last year from BestBuy and so far I consider it as my worst purchase ever.
I haven't been able to deal with the issues the camera has. GoPro customer service is useless and they don't offer solutions but some homemade workarounds.

GoPro seems to have no quality control department (neither in development & manufacturing nor in customer care). They probably released this camera without proper testing and bug fixing.

I have noticed following issues with this camera:
1. Overheating - the camera becomes very hot at 4K video mode within 10 minutes and shuts down. I almost burnt my fingers while removing it from mount. Customer care is pathetic - they will suggest you to use camera at lower resolution which is ridiculous - I would have bought HERO4 Silver (that $100 cheaper) if I wanted lower resolution.

2. The GoPro App sucks - I got it working once but after recent firmware update - no matter what I do - I don't see any preview or live feed in the app. Customer care will give you funny solutions - turn off data connection, turn-off Protune, reset camera, reset phone etc.

I spent another $79 for an LCD Touch Backpac because I was frustrated by the fact that I can't look at preview when I want to - that turned out be waste of money - the LCD extension can't play back 4K videos - I tried several times but screen just turns white and you don't have any option but to remove and reinsert battery. Moreover camera overheats quicker with this LCD screen.

3. 4K videos are choppy most times - 1080 works fine but what's the point of paying for 4K then. Customer service suggested me to get SanDisk Extreme/Extreme Plus memory cards - I bought Extreme plus (which are costly) but no improvement in video quality.

4. Lastly - GoPro Studio Desktop application is of no use - it crashes frequently on both my laptop and desktop (I have Intel i5 processors with SSD as main drive and all other programs work smoothly, just GoPro Studio has problem).

Their customer services seems to be copying-pasting some scripts, they don't really have a solution for customers. I spent almost $1000 in this camera and accessories and I consider that money wasted now.

Keep it ventilated during long shoots under the sun. I just had to tell a client that his 3-day time lapse of an event is DOA because I was more concerned about moisture than ventilation. GP4Black was setup on roof top, no shade, inside case, plugged into AC power (I use a LongShot power system) with internal battery installed and 64GB Sandisk Ultra microSD and WiFi on connected occasionally to app. I've done this setup many times without fail, only variable this time was a gorgeous, sunny mid-70's Kansas day in early March. While the thermometer reading didn't look high, the direct sun was strong.

It was capturing 12mp Protune stills every 5 seconds. It would normally run 24 hours fine or until the card filled up. This time it ran from 8 A.M. to 1 P.M. and shut down. My only clue that it might have been overheating is that it was powered down when I came to break down the gear. Power button turned it back on, everything checked out, as if someone had just come by and hit the off switch (the thought crossed my mind, but it was on a secure roof).

Despite having a sunshade and small PC fan that I use during extended (week or month long) time lapse shoots, with solar panels, deep cycle car batteries, etc, I just overlooked the overheating possibility, probably because it was 16 degrees here a couple days earlier.

I still give the camera 4 stars, and am leaning towards 5. With proper forethought and setup this could have been avoided, it's on me. That's why I logged in to pass the word along: keep it cool!