I built my keyboard using this: https://keeb.io/products/quefrency-rev-4-65-split-staggered-... and I've been happy with it for the last few years.
I used to have really bad hand cramps and this saved my hands (and probably my career). Best keyboard I've ever had, by a large margin (both ergo and not, mechanical and not).
https://www.amazon.com/gp/product/B008PFDUW2
It was the only mechanical keyboard I could find that fit the following requirements:
* no fancy RGB lights * full 101+ keyboard - meaning it has a numpad on the right
What's so special about these RX switches? The PBT keycaps are mounted on 4 corner posts absolutely eliminating any key wobble while having a very decent amount of travel. The switches are optical and tuned to very light actuation (this being a gaming keyboard). After typing on this keyboard every other keyboard feels somewhat sluggish and wobbly.
For the layout I use the typical QWERTY.
https://www.logitech.com/en-us/products/keyboards/k120-usb-s...
Layout: modified azerty. Some things are where you'd expect them, but about 10 keys are remapped and moved around.
I like splits. Sadly, many of them don't have a dedicated row of function keys (F1-F12), which I use rather a lot. I've built my own a couple of times over the years, but the Kinesis is good enough.
qwerty, because my home keyboard isn't the only one I use and I don't want to bother with changing to dvorak or colemak or whatever (I used those two at various points), and even though I'm typing somewhere almost every day, including occasional transcriptions, I'm fine with 70-80 wpm and and having to reach a bit.
The main keymap is Colemak (unbelievably comfortable compared to QWERTY) along with a bunch of custom layers for the other stuff. I've written more about it on my blog (https://snprajwal.com/blog/ferricy-custom-split-keyboard/)
I have had it since it came out (I think that has been about 2 years now). It has had the best ergo layout I have tried for programming. I think a big part of it is the palm (fn) button is so nice for getting to alternate characters without feeling like I have to strain for a modifier key.
With a custom keymap, but still using QWERTY. Ben Vallack on YouTube has some great videos on minimalist layouts: https://www.youtube.com/watch?v=8wZ8FRwOzhU
https://www.keychron.com/products/keychron-q2-pro-qmk-via-wi...
Same one as in the top photo here: https://rudra.dev/keyboards/northgate_omnikey_ultra/ (note, not my blog, just one that I found with a photo).
Office: ZSA Moonlander
Both programmed with a slightly adapted US layout and ESC instead of caps lock. Plus I have "hold down ESC" as a layer for very primitive vim binding simulation for Windows (e.g. mapping hjkl to arrow keys or b to ctrl-left and e and w to ctrl-right).
I am using the Dvorak layout, as I have done all my life; it works well enough that I have never bothered to try anything else.
The current price of this keyboard is $18, and I prefer it to the Kinesis Advantage I used to own (current price, $349).
V1 had some issues, V2 is better.
With custom layout
Qwerty