The Datahand is a great tool for folks with severe injuries that make it painful or impossible to type on standard keyboards, but I wouldn‘t recommend them to someone healthy. Even the fastest Datahand typists I’ve seen only achieve moderately high speeds (though to be fair they can’t type on anything else, so that’s still a great boon). Sourcing used Datahands is difficult and expensive, and they have an extremely steep learning curve.

I’ve only ever tried typing on one for half a day, so don’t take what I say as gospel, but I’ve spent months thinking about keyboard shapes and hand anatomy, and my opinion is that many of the motions used by the Datahand are inherently awkward and slower to repeat or coordinate than the motions required for typing on more standard-ish keyboards. The idea is to use semi-awkward motions, but actuate with a very light touch, so that not much force is required, reducing impact shock. This is great for folks with injuries, but not the best way to optimize for healthy typists.

The standard keyboard does have significant flaws, but these can be solved in better ways, more closely aligned with human hand anatomy. Even on a standard keyboard, it’s possible to type without injury.

Here are some recommendations to help stave off RSI:

(1) Most importantly, keep your wrists as straight as you reasonably can. This is more important than any other aspect of typing technique IMO. Make sure to tilt the keyboard such that the plane of the keys is parallel to the plane of the forearms. Try using a low desk and/or a high chair and bringing the keyboard in close to the body to allow typing with the upper arms hanging down loosely instead of extending outward or forward, and the elbows at a >90° angle, with the wrists and palms floating in the air rather than resting on any surface. (2) Try to type with a springy light touch, and use only a little more force than absolutely necessary to actuate the keyswitches on whatever keyboard you use. If the keyboard is a cheap rubber dome board, and the keys must be mashed down hard to function, get a different keyboard. Mechanical keyswitches are much more comfortable for long-term typing. (3) Take brief breaks from typing every 15–30 minutes and longer breaks from sitting every hour or so. Stand up, stretch, go to the bathroom or get a fresh coffee. Walk around the block and think for a while if you want. Don’t type for 8+ hours/day if you can help it (you probably can unless you’re a data entry clerk or transcriptionist, and those jobs are getting rarer these days). (4) Try to get enough sleep, exercise, eat well, and avoid too much chronic stress.

For someone who wants something better (more efficient and more comfortable) than the standard layout:

(4) Try a split keyboard. An otherwise-standard split keyboard is a good gentle-learning-curve alternative, look up the Matias ErgoPro for the best one currently on the market. If you’re braver, try a Maltron or keyboardio. (5) Change the logical layout, try switching away from QWERTY to a layout that requires less awkward/uncomfortable motions. Most usefully, remap common functions like backspace, return, shift, escape, and arrows to more convenient locations. Add multiple layers and place common symbols and functions near the home row on a layer instead of at the far corner of the keyboard.

I could add a bunch more suggestions, but this comment is long enough for now.

Everyone come ask questions and chat on the Geekhack keyboard ergonomics forum! https://geekhack.org/index.php?board=125.0