Likes:

The layout really wakes you up to how (key distance) inefficient QWERTY is.  Almost to the point where I sometimes miss letters - not because of muscle memory - but because my hands have become so lazy to almost bark back: " 'F' can't possibly be up there!  Everything I need is on the home row!"

I like that I can click on a colemak.exe program and instantly have the layout (despite not working on login screens.)  Honestly I am a lazy bastard and if this .exe didn't exist I probably wouldn't have bothered.

A lot of enthusiasm and general acceptance despite its creator not presenting any research or documentation:  TypeMatrix has Colemak support in it with Colemak "skins" on the way.  I also heard that the makers of the QIDO Dvorak adaptor are implementing Colemak support (even if it will be $$$)  Linux already has it, The next Apple OS is supposed to have it, and I wouldn't be surprised if Windows was to follow suit.

I like that it was quick to learn and that the short cuts stayed right where they were.

Dislikes:

When I started learning Colemak my right forearm felt really tight like it was getting overworked.  This has gone away completely however it has been replaced with pain in my right wrist after extensive typing.  For the record I've been typing in QWERTY for a while and never had any pain.

Despite having more words on the home row I wish there was some more alternating.  I would really love a Colemak-A layout that took everything Colemak is good at and add a little more alteration with the hands.  What my hands (and statistics) have been telling me is my right hand is getting put (efficiently) through a meat grinder.

Along with my previous comment I want to see some research and studies conducted.  I don't care about studies on speed: I want to see doctors specialized in hand surgery approve or recommend this layout.

The Colemak crowd can sometimes be a little ridiculous.  If Colemak were a car it would most certainly be a Toyota Prius.  There seems to be some sort of "right vs. wrong", "black and white" attitude.  I can understand some folks being enthusiastic but it is off putting to say the least.  The "S" issue in Dvorak is crazy because Colemaks "O" is a higher frequency character by +-1%  The "L" is where the "P" is in QWERTY and I've never had a problem with pinkys in QWERTY so your mileage may vary.

Conclusion

I think for the near future I am going to stick with it.  I am saving up for a Kenisis keyboard ($$$!) to see if I can alleviate the symptoms in my right hand.  However if I can't get the money fast enough (with in 3-6 wks) I may ditch Colemak on a Friday afternoon and use all weekend to get Dvorak down so hopefully by Monday morning I can at least churn out 20wpm and be somewhat productive.  I don't want to make this sound like I am a closet Dvorak zealot.  The more I hear about hand alteration in Dvorak the more the siren sings to me.

Just remember, a layout is only as good as your ability to type comfortably.