Whenever the Kinesis Advantage 360 starts shipping, that might be a good option for trying out a split keyboard.
They have 60 day returns and don't fight you on RMA at all: https://kinesis-ergo.com/support/returns/
They have 60 day returns and don't fight you on RMA at all: https://kinesis-ergo.com/support/returns/
The thumb keys are also extremely important, but they're more common among ergo keyboards. I don't think I'd ever buy a keyboard without thumb keys. Thumb keys go great with emac's standard keybindings.
I've spent too much money on keyboards already, but will very likely buy the 360.
There are some DIY keyboards like the dactyl-manuform that also look great. Could be a fun project, but I'm not really looking for more side projects at the moment.
They are pretty expensive, but you can get a custom Dactyl Manuform made for about $400-500. I think there are some cheaper ways to get one. I made my own and its the best keyboard I've ever used. Before that I was using a different split keyboard (the ergodox-ex) and it was pretty good but the Dactyl is near perfect. I just wish they were popular enough for a large manufacturer to start making some non-3d printed cases for them.