If I'm going to spend more than a hundred bucks on an item or somewhere around there, I do extensive research first to know I got the best bang-for-the-buck and, consequently, dodge any potential future buyer's remorse.

I've realized that the time I spend doing my product comparisons is often time that others don't have so I may as well share what I can.

I'll start by saying that you'll see my "Verified Amazon Purchase" on the Flip HD Ultra Camcorder review because, obviously, that's the one I wound up buying and I'll share with you why. But what I like in a camcorder may not suit your own needs so I'll break it down and let you decide what's best for you via what I found out:

Here are the pocket camcorders I compared:

Flip UltraHD (will be referred to as "F")
Flip Mino HD 2nd generation (Will be referred to as "M")
Creative Labs Vado HD 8 GB 2nd generation (Will be referred to as "CL")
Kodak Zi6 Pocket HD (Will be referred to as "K")

Why HD cameras only? Brighter colors and better images, wider images

HD SHOOTING TIME:
F: 120 minutes.
M: 120 minutes
CL:120 minutes
K: 25 minutes with batteries they included, 120 minutes if you buy an SD card

MEMORY:
F: 8 GB
M:8 GB
CL: 8 GB
K: internally only 30 MB recording space but it has 32 GB expandable SD/SDHC card slot. Because it comes with such small recording space you really need to buy an SD or SDHC card to maximize its potential, but the potential is really good and this will increase your ability to shoot longer.

RESOLUTION:
All 720p which is excellent, just one step below the top 1080p format.

MICROPHONE:
F: Stereo
M: Mono **Update** They are now putting Stereo Mics in the Minos as of 2010.
CL: Mono
K: Mono

SOUND:
F:Premier AAC audio. Best stereo sound quality but still not great in winds
M:Good sound quality. Still not good in winds.
CL:Poor sound quality; had issues with sound and picture not being in sync.
K:Poor sound quality

ZOOM:
F: 2x
M:2x
CL:2x
K: poor quality zoom on the one I tried but I still think it's 2x. It has a great macro focus for very close-up objects if, for example, you see a bumble bee and want to shoot it on a leaf a few inches away! Kinda cool.

CAMERA SIZE AND WEIGHT:
F: 4.3x2.2x1.2 4 oz
M: 3.9x2x0.6 3. 3 oz
CL: 3.9x3x0.6 3.5 oz
K: 5.5x2.5.0.9 5.6 oz

SHIPPING SIZE AND WEIGHT:
F: 6.2 x 3.1 x 3.1 inches ; 11.2 ounces
M: 2 x 0.7 x 3.9 inches ; 1 pound
CL: 3.3 x 7.9 x 6.3 inches ; 11.2 ounces
K: 4x 5x 2.5" 2.4 lbs

TECHNICAL DETAILS:
F: USB cable pops out of the back so you don't need to keep up with a separate cable. Comes with Flip Video rechargeable AA battery pack (recharges when connected to USB); also supported by standard AA batteries. Note: Some sets come with the HDMi mini included and others come with the rechargeable battery pack on Amazon. Looks like one or the other but of course if you need both you can buy the other.
M: USB cable pops out of the back on this one as well. Has child safe button to prevent accidental deletion of videos. Internal lithium ion battery recharges through built-in USB arm
CL: USB in camcorder. Included in box are HDMI cable (nice), USB extension cable,(nice)silicon skin (cool) & rechargeable battery.
K: Included in box are HD and AV cables and wrist strap and rechargeable batteries and battery charger. Has built in USB arm.

SPEED:
F: 30 frames per second.
M: 30 frames per second
CL: 30 frames per second
K: choice of 30 frames per second or 60 frames per second.

VIEWING SCREEN: All 2" except the Kodak was the largest at 2.4"

IMPORTANT NOTES:
F: Best low-light performance for the mini cameras (though not perfect at all) and least amount of blurring and dropped frames in my opinion. Best color. Only one with stereo sound. You can get an underwater case for this one! Though that may sound crazy for a Texan, we use the camera non-stop on vacations and even when we aren't IN the water, we are around the water...on boats, in the sand with sea mist, etc. Then we can dive in and record the fish. Comes preloaded with flipshare software...just plug in to computer and it pops up. Only one with stereo sound.
M: Colors don't appear as good on the Mino as the other cameras. Thinnest camera. Make sure you get the one that only comes in the color aluminum or brushed metal. If it comes in any other colors it is the 1st generation MinoHD and they improved upon that one in the newer models. Great audio. Better shooting in low light than most mini cameras. Camera comes preloaded with FlipShare software. Can get still images through flipshare software.
CL: Decent filming in low light but not nearly as good as the Ultra or Mino; Software is preloaded in camcorder.
K: This is the only camera that I compared without the built in image stabilizatin which corrects for shaky images. What appears to be metal in picture is actually a chrome colored plastic. That said, this had the largest viewing screen of all of them. 2.4" Very poor in low light and seemed to have far more shaking and blurring. It also takes still pictures but they are really really poor quality...same as a lesser-quality cell phone pictures but good in a pinch if you want a still shot and have no cell or camera I s'pose. Heaviest for a pocket camera. Software is not preloaded in camcorder but a cd comes with it.

HOW CNET'S EDITORS RATED THE CAMERAS:
F Excellent
M Excellent
CL Very Good
K Very Good

And, finally, the reviews of the Flip from experts swayed me quite a bit:
Fast Company: "Flip Ultra HD is Pure Digital's "Best Pocket Camcorder Yet." 6-09

USA Today: "New Flip Ultra Video Cameras Might Flip Your Switch" 4-09

Business Week: How do you Invigorate a Recession? Look to i-phone, Flip, Kindle, and Zip Car For Answers

There were lootttts more I came across when researching the Flip Ultra HD but those are some of my favorites.

CONCLUSION: Clearest picture and sound was important to me, expert reviews that pointed to the Flip UltraHD as well and I liked the built in software and the case I can get to shoot underwater. It is the number one selling camcorder as well. So that was my personal decision-making process. However, keep in mind that if you need reading glasses none of that will matter if the 2" screen is too small for your viewing the shots easily for playback in which case you may wish to get the Kodak if that's important to you..

Also: No matter which one you get, you will probably want a mini tripod if you ever want to be in the shot yourself do don't forget those.

Also note: It's confusing because when these manufacturers make changes in the camcorders, they do not change the names on the new versions, nor do they change the names if it's an HD version or a non-HD version so be sure you look for the "HD" after the brand name and look for "2nd generation" or "newer version" on the Mino and Vado if you like one of those better so you don't get the older models.

Hope my obsessive comparing and contrasting for my own purchasing assistance helped you as well even if what you wanted in a camera was different from me. :-)