For a while before I switched, I was kind of curious about keyboard layouts, originally wondering why I would switch from QWERTY. So eventually for kicks I tried Dvorak. Hated it. Mainly because it was just SO different and realizing most shortcuts I use would vanish. After watching Youtube videos on others' opinions on Dvorak, some folks mentioned Colemak. So one night I pulled up an online typing program and tried it for fun. DANG I never knew I could type so slow, but it became a curiosity, so I tried it more in my free time. I thought, hey, if this does happen to be a useful keyboard layout, maybe it will help with my gradually-getting-worse wrist pains from sysadmin work and programming and school. Boy did it take a while though. But now typing feels more natural, my wrist pain IS reduced, and when I type I don't feel like my hands are flailing around like a fish out of water.
So to fill in info from Shai's list:
* I've used QWERTY before like most, and I didn't really start learning to type until 2nd grade soo...it's been 15 years of it.
* I have used Colemak daily now since mid November, so it has been 3 months, and I type maybe 3 to 8 hours a day
* When I started to learn Colemak, it mainly started with me using an online typing program (thetypingcat.com). I honestly was able to memorize the entire layout in one night. I would also at random times try to go through each row in my mind when I wasn't doing anything. Eventually, I tried typing what I could with Colemak, but saved the big stuff for QWERTY when I still needed speed. After 3 weeks I decided to take my typing and put it to the test, as the last time I tested my speed it was 20WPM (from my usual 100WPM). So I decided to take notes one day in class. WOW I WAS KEEPING UP!! So from that point, I just stuck with Colemak and typed everything, maybe switching once or twice to QWERTY from time to time. After one week my speed went from 30 to 35, then 35 to 45, and in 2 months I got up to the 50s consistently! All in just over a month of time. That was my progression and "path" I took to learn Colemak.
* For my operating systems, I use Windows 10 (secondarily) and Fedora mainly. My findings with Windows 10 is it keeps capslock and backspace all in one key, along with Fedora with KDE, and I think my FreeBSD servers too. Fedora with GNOME actually disables capslock!!! So I can use backspace properly now when I actually remember it's a thing right there. I also recall NetBSD doing this properly too (aside from it nuking the usability of numpads and whatever you call the insert, home, delete, etc. key grouping).
* For speed tests I mainly just use Type Racer.
Progression:
-Day1 - Probably 5WPM
-Week2 - About 10WPM
-Week3 - About 15WPM
-Week4 - 25-30WPM
-Month2 - About 50WPM
-Month3 - Current, 70-75WPM
I think the thing I can share most about tips for learning Colemak are to use it with an open mind. One of the biggest turn offs I see with people are that they don't perceive a need so they bash the idea of changing, even dissing legitimate truths about Colemak or just ignoring it. It's cool to not want to switch, but it's not cool to fling insults at a user or the concept of using an alternate layout. But at least I can return with obvious reasons Colemak is better and they have nothing ;) Just be certain you want to switch because it's actually hard to go back and you have to rebuild what you lost (PS - it's NOT worth going back)
Criticisms - well, where's my Right Alt key!??! I used that thing! Mainly for switching workspaces with one hand if my left hand is occupied with something (like food or coffee)
For me I think the worst thing about switching has been using Colemak on a QWERTY keyboard. It's no problem whatsoever when I type regularly, but if I have to finger peck something it's impossible. Kinda like translating from English to Spanish on the fly if you don't really know Spanish. And for Linux/UNIX admins: eventually you begin to get used to typing CLI commands with the new layout, and generally, it's nicer to type them on Colemak once you're used to it.