So Canon released firmware update 1.0.6 and I just updated my lens. In my unscientific test shots I can confirm that the front focusing issue is indeed fixed. Funny thing since using it, I never in real world use shot MFD at 200mm. Well it's nice to know it fixed though and big props to Canon for addressing it in short order. Also you will be happy to know that I put it through slightly harsher environments and the lens was fine. Took it out in the rain and some dustier locations and no issues. So back to 5 stars you go.
EDIT: 12/3/2019
Okay, so it came to my attention that some others were having issues with this lens front focusing when shooting wide open and a minimum focus distance. I decided to test it myself. I shot a small figure that has several towers on it. I aimed it at one particular tower in the back. Sure enough, the tower slightly in front appears sharper. Others have done far more scientific tests using a target card and indicating that the lens front focuses by about 3mm. It's so minute but it's right there... repeatable every time. Knowing that, I've docked it from a perfect 5 stars to 3 as that's obviously a flaw for something so premium. I mean it's a very unique case shooting wide open and MFD so it still works in most other cases, it's just that if you need to hit focus on a razor thin DOF from up close, you need to use manual focus. I'm optimistic that a fix is on the way though as it seems like Canon service centers are aware of this since I know of others having sent there lenses off and the issue is seemingly universal and consistently reproduceable. That bodes well for hopefully a firmware update to universally rectify the front focusing issue. Be happy to add the stars back once it gets fixed.
Original:
I preordered it and I just received this today, so this will be my initial thoughts on the lens. As I progressively use it, I'll provide updates. Not a photographer by profession, but love photography and videography. So I am a hybrid shooter who does equal parts photos and videos. In the few hours that I've had this lens, I'm completely floored.
Build
I have never owned an EF 70-200 f2.8L so couldn't tell you how they stack up. I do know that it is lighter than the EF variant, and the big kicker is that it turns into a short little stubby lens at 70mm. I know many who elect to leave the EF version at home because of the size and weight. This will be lighter in the hands and more importantly, at it's smallest it will take less room in your camera bag. When fully extended to 200mm it's about the same length as the EF version. It feels solid in the hand, and the ergonomics are familiar. The focus and zoom rings feel smooth and nice. The control ring is both too tight and loud for me. If shooting video, turning the control ring will cause camera shake, and a mic will pick up the clicks. I've sent my other lenses to get declicked. If they come back and solve these issues I may send this guy for the modification as well. Some are concerned about this lens extending as opposed to being a fixed lens like the EF version since there may be a propensity for sucking in dust. They do say it's weather sealed, but I will need more time with this lens before I can report on if there are any issues with an extending zoom. I do not beat up my lenses too much, don't shoot in extremely harsh environments. Maybe the worst place will be a windy beach with fine sand. Will report if I have any issues. The lens hood is cool. I don't know why, but I like how it matches the lens. I think the EF versions have a black hood, this one is white and looks cool, lol. It has a sliding window that opens so you can reach circular polarizers or variable ND filters.
Auto Focus
Wow! Totally blown away by this. I do have the latest EOS R 1.4 firmware at the time of writing this review and the autofocus is super snappy. Something about the RF system where I feel like I'm hitting focus so much more of the time. My other camera is a 5D Mk IV and I swear I'm nailing focus more often with the R and RF lenses. This lens is no exception. The other thing that blows my mind, is how ridiculously silent the focus is. I literally cannot hear it... at all! Well, if there is some ambient noise, you cannot hear it. In an absolutely silent environment, you can hear the faint clicking if you put it close to your head. It does have a double motor USM system which I believe is a first for Canon and if that's the reason for it's silence I'm impressed! For comparison, the RF 50 has a little noise. The RF 24-70 a little quieter. In a little ambient noise this lens is dead silent.
Image Quality
I originally was not going to buy an EOS R. I was waiting for the "pro" variant. I always knew I was going to get into the system because the RF lenses are almost guaranteed to give you amazing image quality. Two things changed. The RF lens line started to fill out, and the EOS R price dropped. So here I am. Could not resist the sweet RF glass. I mean I set the bar pretty high with my expectations. All I can say is I haven't been let down. The photos I've taken are random things around the house, but the detail, edge to edge sharpness, color rendering, smooth bokeh and lack of distortion are all top notch. Telephoto is my favorite type of focal length, and this pretty much is the dream lens. For comparison, I have a 70-300mm f4.0-5.6 and a 100mm f2.0 IS Macro. Image quality blows my non-L EF lens out of the water. Many say the 100mm is one of the sharpest lenses. With the few shots I got, I think this is right there with the Macro.
Low Light
Just quickly did a few tests. As long as there's just enough light on a subject, the AF is just as snappy as it is during the day. I lock my ISO off at 6400, and to my eyes, noise level is great. The f2.8 aperture and three levels of stabilization really help. Speaking of...
Image Stabilization
Okay, so there are three levels. I'm not sure if I'm using them properly. Apparently Level 1 is for a single shot. Level 2 is for panning. And level 3, which only activates during exposure. For video it works amazing. Look at the two videos of the bird on a wire to see the difference. (Edit: Could only upload one video, will make a composite at a future update.) Night shots were great too. I didn't stop exposure down too much, but still, the night shots are crazy sharp.
Video
Video quality is great. I already alluded to some of the pros and cons. Focus motor is super quiet so won't be picked up on a microphone. The focus pulling was razor quick. As seen on the sample video. I did not mess with the settings on the Camera but I believe these can be slowed down so you get a smoother focus pull. The control ring is unusable during shooting. It is both too loud and too tight. If you don't plan to get it declicked, it's use is best for pre-shot adjustments to ISO, exposure compensation or whatever. At least you'll be less likely to accidentally change settings.
Samples
These are straight out of camera JPG's and MP4's. Yes Canon Color science is real. Unfortunately I guess I can only upload one video, so it's the bird on a wire with Image Stabilization.
Conclusion
I presume this will be a staple for pro wedding photographers, sports photographers, wildlife photographers who buy into the RF system. They will likely appreciate the new lighter smaller form factor. But really, I believe anyone with the funds to afford this will enjoy it. The cost is certainly expensive, but I do think it is worth every penny. It's just that much of an upgrade in handling and being able to nail focus a greater percentage of the time. Keep in mind, this is me using it for all of a couple hours. It's just handling it, I could immediately tell that put through it's paces it will perform.