When comparing Colemak vs Arensito, the Slant community recommends Colemak for most people. In the question“What are the best keyboard layouts for programming?” Colemak is ranked 1st while Arensito is ranked 11th.
Ranked in these QuestionsQuestion Ranking
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 Reduces load on pinkies
Pro Emphasizes adjacent finger bigrams
Common bigrams are a fast rolling motion, like Colemak.
Pro Minimizes same-finger bigrams
Pro Puts your thumbs to good use
Your strongest fingers are your thumbs. In this layout (unless you have a keyboard with thumb keys) you shift your hands up one row, and you use your thumbs on the bottom row. (Put your index fingers on QWERTY's
I keys, and rest your thumbs on VB and NM) The Ctrl and Shift modifier keys now use your strong thumbs instead of your weak pinkies. (Ctrl shortcuts are especially important for programmers.) The modifiers may contribute more to RSI than letters.
Pro Punctuation also optimized for programming
AltGr plane has accessible punctuation and numbers. The most used are directly under your fingers on the (new) home row, and all the bracket types are paired and in easy reach.
Pro Balances load between hands
Statistically, the left and right hand are used about the same amount.
Pro Easy access to common punctuation and numbers
Programmer punctuation and numbers are accessible without stretching on the AltGr plane. (AltGr is now on the spacebar).
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.
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 Pointing stick is no longer on the home row
Most keyboards don't have one, but if you use it a lot it becomes a bit of a stretch. On the plus side, a keyboard with a pointing stick will have mouse buttons you could remap to thumb keys instead.
Con Hard to orient in a new position by feel
Most keyboards have bumps on two of the keys to orient touch-typists. On QWERTY, this is usually F and J, but sometimes D and K. On some keyboards you can fix this by swapping keycaps. You could also try adding small stickers with enough thickness.
Con Letter keys as modifiers may cause jamming or ghosting
Cheap keyboards designed for QWERTY might struggle with the use of Arensito's letter keys as modifiers. Gaming keyboards with n-key rollover don't have this problem. And any keyboard with proper thumb keys (Kinesis, Ergodox, Maltron) works properly. There is an older version of the layout that keeps QWERTY's home row that you can use on cheap keyboards, but it's not quite as nice.
Con Copy-paste shortcuts are right-handed
XCV are on the right side. This makes it difficult to cut/copy-paste with the mouse in the right hand.