L.S.,
I am of the "just before digital hype" generation; I have used DOS and Windows 3.1 before puberty. Putt Putt, Fatty Bear and "format C:" were my hobbies. So, I learnt using QWERTY by myself at a young age and never desired learning an alternative.
Probably a couple of months ago, I felt the urge to try something new. I was not dissatisfied with typing in QWERTY per se, but I wanted to know how easy it is to change habits. Was it a matter of training and effort? Or patience?
So, I investigated Dvorak but quickly learnt about Colemak. I installed the layout on my Windows 7 system and set it to be my default layout. I also modified my physical keyboard to resemble Colemak. I also installed the training program, but I haven't really used it apart from measuring my QWERTY typing speed (100+ wpm).
Setting the Colemak layout to be the default really helped to face this challenge. Every time I had to write a long text, I would reset it to QWERTY, but for all other programs (defaulting in Colemak) entering my input with Colemak, instead of switching to QWERTY all the time, was exactly the right small repetitive "chore/challenge", I find.
I use my computer a lot (perhaps 10 hours or more a day). You understand problems with typing are really annoying. I believe I quit using Colemak once or twice in the learning process, frustrated by the many typos. Even worse, there were these two weeks I couldn't seem to type in either Colemak or QWERTY. I actually felt as if I was degenerating. But then, some day, I seemed to suddenly "get it" and I could type in Colemak. Even now, it's no longer a hassle and I can dream the layout of Colemak almost as easily as I could for QWERTY. Typing speed is probably around 75% of my old top speed.
What I love about Colemak is, first and foremost, the extra backspace. Moving the semicolon from the homerow was a good decision too. The new combination for special symbols are also rather well thought-out. Sadly, Colemak is worse than QWERTY for the Dutch language, it seems. The often-used "ij" combination are distanced awkwardly; the 't' and 'd' are close together, while the "dt-mistakes" are already notoriously often made errors in the Dutch language (for grammatical reasons).
I also noticed a severe degradation in my QWERTY typing skills, since working in Colemak full time. I presume that "explicitly learning" Colemak has stupefied my QWERTY skills that I learnt as you learn walking. Even now, I can't remember the QWERTY layout anymore. I have read these skills are not lost and can be easily "re-awoken", so perhaps I need to revert to QWERTY for a while. Not knowing QWERTY is really annoying when working on the computers of others (which happens often).
All in all, Colemak has not changed my life yet. I do enjoy typing in it and I probably benefit from using the homerow more. Still, I don't know if I would recommend Colemak to others, given the cost of losing QWERTY skills, temporarily or not.
Thanks for reading!