Many people, including myself are in a search for the ideal keyboard. The definition of ideal is different.
The standard 104-key boards do work just fine provided:
- user's posture is ideal: straight back, the keyboard at the waist level, arms are free, elbows are not on the desk, etc.
- the keyboard is used almost exclusively for the plain text typing, no editing,
- no or little need in mouse use.
When those conditions are met - no need to use a custom board at all.
The issues arise when they aren't.
In most cases the keyboard is placed on the desk which is too high; the work requires constant navigation through the text, menus and toolbars, entering numbers, using other non-letter keys in combinations with modifiers; some apps are impossible to use without the mouse.
All that makes the regular 104 keyboards inefficient and at best. Hands are held in incorrect/uncomfortable position for prolonged time, the stress is accumulated and over time becomes a problem.
The mass-market keyboard vendors are trying to help, there are many quite popular keyboards with "ergonomic" in their names, e.g. Microsoft 4000, Logitech K860, Lenovo Go. Unfortunately, they are not much different from the regular ones. The reason seems to be the intent to change the design without changing much. All the layout is kept the same, just stretched and turned to a bit more comfortable angle. Good start, better than regular boards, relatively affordable, still far from ideal.
Less known manufacturers like Goldtouch, Mistel went a bit farther, and introduced split boards. Those provide more flexibility in hand placement, so the halves could be tented and tilted as desired. Again, they are much better than the regular boards, but they tried not to scare the potential buyers too much. My biggest problem with them were the text navigation and editing keys and (at the moment of me trying them) lack of configurability. They are usually located in uncomfortable places as an afterthought, in more or less usual place.
Specialized keyboards like Kinesis Advantage got ever further, organized keys in the wells, added more keys under the thumbs, spread the halves or separated them completely. That brought them much closer to my ideal, except for the price and the key arrangement, and limited customization options least at the moment I reviewed/considered them.) They still tried to provide all the regular keys on the default layer. That seemed to be a bit too much, all the benefits of key wells and separated hands were overridden.
Then there are other "enthusiast" options, Ergodox and its clones. They got the split halves, fully programmable, got elaborate thumb cluster. They got too many keys, but luckily they could be largely ignored, with the easy configuration and their support of multiple layers.
Finally, there is Dactyl-Manuform and other 3D-printable boards. They allow any imaginable form and key placement. The drawback is the assembly. Yes, there are more options now, flexible PCBs with hot-swap sockets, much better, but require quite some time to assemble. Very good for the custom orders, impractical for multiple copies.
So I combined those options into a PCB-based keyboard. It was to repeat finger locations of one of my latest DM versions. 4x12 with column-staggered split halves, with the thumb cluster reduced to two keys and raised for about 1 1/2" above other keys.
Wait, but your keyboard is not split but a unibody! Yes, soon after making the first iteration of the PCB-based board I realized I used them placed closely, either on top of my laptop keyboard, or even on my desk. The raised thumb cluster reduced if not eliminated the hand pronation, much better than the prior experiments with flat boards.
It was only logical to un-split, connect the halves, and this gave me this board.
So here is another custom keyboard which is ideal to me.
There are other more subtle points related to the key arrangement, layers design, usability, comfort. I will cover those topics separately.