Define “fancy” and “custom” 
How much do you want to spend?
Do you want something off the shelf, or customized to your preferences?
- Do you want clicky switches, switches with a tactile bump, or none/silent?
- Do you want custom keycaps? What key profile do you like?
- Do you want backlighting?
- How many keys do you want? (function keys, ten-key pad, navigation cluster)
- Is programmability important?
- Is the type of firmware important (i.e. QMK or something else)
Keyboards I’ve retired and why
I have several in the closet, including a Moonlander, a Keyboardio M-01, the predecessor to their Model 100, a Kinesis Advantage2 QD, a Matias Ergo Pro for Mac
The big thing for me that makes the Moonlander and Keyboardio not work for me, is the ability to type chords of modifier keys. E.g. the Moonlander has the nice thumb cluster that can be Command, Option, Control, etc. but you can’t type Command+Option with your thumb, unless you put your thumb between. Then if you need Command+Option+Control, you need both thumbs, a finger, and carefully plan to be able to reach the letter that you want to press in conjunction. Whereas with my CTRL (and many other) keyboard, index, middle, ring fingers on one hand, and a finger on the other hand for the letter.
Moonlander and Keyboardio are also very programmable, and you can program braces, parens, etc. to be accessible with one finger, but you have to remember and retrain yourself, and I find the cognitive load of that to be too great. Neither have F keys, nor the inverted T arrow keys, plus other navigation keys like Home, End, etc. Of course these can be programmed, but - more to remember.
The Kinesis Advantage didn’t fit my hands. I felt like I had to contort my hands too much to press keys on R4/R5 (ZXCV… on a Qwerty keyboard), and was constantly stumbling on other keys.
The Ergo Pro and other split keyboards - there was too much ambiguity in where the halves of the keyboard were spatially. With a one-piece keyboard, there are fingers on keys at all times, and it’s easy for Brain to calculate distances to keys on the same or other hand. Also, the F keys are weird.
Switches
If you’re going to get custom switches, I recommend buying a switch tester so you can get a feel for the different switches - clicky, silent, etc. I prefer Cherry brand, but there are others available. There are tons of keycap sets for Cherry MX-style switches.
My Daily Driver
It’s a Drop CTRL, in Black with MX-Blue (clicky) switches. It has the Bladerunner 2049 keycaps from pimpmykeyboard.com. These keycaps are DSA profile, which is quite flat. If I had my druthers, they would have been SA or DCS profile, but they’re Bladerunner so that overruled. FWIW, I have several extra keycaps left over and could change the color scheme, use conventional keycaps for all the F keys, etc.
It’s also very programmable, and uses QMK firmware, so I can have my usual Dvorak key mapping, plus another ‘layer’ that is Qwerty to ease some login pain. For comparison, the keyboard was $250, and the keycaps were $194.
I guess the most important thing is, with this keyboard and my Logi MX Vertical mouse, my wrists don’t hurt.
