A month ago I abandoned Qwerty and regular keyboards and started using Colemak on two (home and work) Kinesis Advantage keyboards. Something I feel I should have done years ago.
I have never tried anything other than Qwerty before, so this was going cold turkey from the only layout I have been using for the past 14 years. The last month have been ordinary working weeks and I used Colemak plus Kinesis exclusively the whole time.
In the first week I did some training exercises that I put together myself on TypeFaster. I also created a crude Kinesis layout for it. But after the first week I got lazy and didn't bother with it.
Currently I can type Colemak fairly well but there is still a lot of typing errors. I might need another month or two before I can type as well as I did before I switched. I don't think that the combination of learning the Kinesis and Colemak has caused any problems. The Kinesis keyboard is quite easy to learn. Unlearning Qwerty is much harder.
The layout I'm using isn't strictly Colemak. All the english letters are the same but since I'm Swedish I had to fit in our three extra letters (åäö) as well. Also, because I'm a programmer I use a lot of special characters. So I wanted to put them somewhere easy to reach. This was the result:
The special characters are typed with AltGr, which is found on most international keyboards. I use a Swedish version of the Kinesis Advantage.
The arrow keys are close to all other keys. There is no need to move the hand to get to them. This was something I found very annoying with ordinary keyboards.
All modifiers are duplicated on both sides of the keyboard so they can be typed with the opposite hand. For example, to type @ the right hand presses AltGr and the left presses a.
The top left button is actually Caps Lock but I have disabled the ordinary Caps Lock usage in Windows. Instead I use it for Push-to-Talk in programs such as Ventrilo or TeamSpeak.
The best thing is that all these modifications are done entirely on the Kinesis Advantage keyboard itself with the help of macros and key relocations. There is no need for special software or drivers. As far as Windows knows it's just a standard keyboard.