When comparing Colemak vs Carpalx QGMLWY, the Slant community recommends Colemak for most people. In the question“What are the best keyboard layouts for programming?” Colemak is ranked 1st while Carpalx QGMLWY is ranked 15th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Much more comfortable than QWERTY when touch typing
Pro Highly ergonomic
Pro You can type faster
Because the home row contains more high used frequency characters.

Pro AZXCV don't move compared to QWERTY
If you rely on the Control-A/X/C/V shortcuts (select all, cut, copy, paste), these keys don't move from their QWERTY locations.

Pro Relatively quick to learn
If coming from QWERTY, only a couple of keys move between hands.
Pro Optimized for quick two-letter bigrams
Not only are the most common English letters on home row under your fingers, but many common two-letter combinations are placed next to each other as well allowing for a fluid "inward roll" motion of letter combos (a-r, r-s, s-t, n-e, e-i, and i-o combos). The inward roll motion is debatably speedier than optimizing finger alternation like Dvorak offers.
Pro Backspace is closer
While the uncommonly used caps lock is further away. May be problematic if you previously developed muscle memory of using caps lock as some other key.
Pro Possibly faster
Most people like the common home row and believes it improves speed in comparison to QWERTY.
Pro Multilingual support
Although it‘s optimized for English, the support for a wide range of special characters enables occasional use of other languages. Still, the Carpalx research shows that a significant improvement is also present in Dutch compared to Qwerty. http://mkweb.bcgsc.ca/carpalx/?de_correspondent
Pro Easier to learn than QGMLWB
Keeps the ZXCV key in the same place as the very common QWERTY keyboard layout. More familiar than even than QGMLWB.
Pro The layout is basically good for most Latin languages
As vowels and consonants are mostly divided between 2 hands and most words in Latin languages are made of 2-letter (consonant+vowel) syllables, the layout keeps it efficiency not only in English, for which it was primarily created, but in other languages too.
Pro It takes much less effort to type than classical layout
The layout effectively combines not only changing hands methods, and rolling fingers as well, that makes typing a real pleasure.
Pro About the same score on the carplax test as the QGMLWB variant
See the source here.
Cons
Con Bad for Vim users
Vim was designed on QWERTY. The HJKL "arrow" keys still work in Dvorak, but their positions make less sense in Colemak.
Con Overrated
People think Colemak is great because it is easier to learn, but in reality they are deluding themselves thinking that it is better than more advanced alternative layouts.
Con Designed for English
Like Dvorak, this layout privileges English letter frequency, and lacks accented letters.
Since the topic is about programming, the argument is weak as most code is written in English, yet you don't want to learn a layout to type code, and another to type in your native language...
But the problem isn't specific to Colemak, it is tied to all "ergonomic" layouts, and might have no solution.
Con The "HE" bigram is awkward
For all of Colemak's focus on optimizing English bigrams, the second-most used English bigram, "HE", is still kind of awkward due to same-hand lateral motion. This bigram is much easier in both QWERTY and Dvorak. If your concern is RSI, Colemak isn't good enough.
Con AZXCV don't move compared to QWERTY
This will allow one to intuitively access popular shortcuts, but the truth is that the placement of these keys is a compromise in terms of actual typing ergonomics.
Con Very unpopular
Even rich on keyboard layouts variety Linux distros like Deepin, offering most of existing layouts, doesn't have this one. The situation on Android is not better, moreover if somebody get used to Swift-like keyboards, that do not have this layout, that person will be forced to have a second (e.g. qwerty) layout in mind.
Con Not always worth trying
The layout is great only if somebody uses it daily and a lot, like journalists, bloggers, writers do. In this case inconvenience to install the layout is worth use it. If you primarily use your phone/tablet to write some comments in Internet and other tiny writing tasks having such an unpopular layout on just your PC/laptop could be not justified.
