unfortunately I can only really work for long stretches on a kinesis split keyboard - with the modifiers all the on the thumb. if they would finally make a bluetooth one maybe that wouldn't be so bad.
I just got an email about a 20% off sale they're having, and I was tempted. Still expensive, though, seeing as how there's so many new ergonomic designs available from smaller companies.
I had a split keyboard and pretty quickly moved on.
The reason should have been rather intuitive, had I considered it. Splitting the keyboard allows a more natural position, but it still needs to be relatively static. Unfortunately, at half the weight, each side had less resistance to moving, especially with the inner stands kicked up at an angle. That meant more frequent fiddling to readjust the positioning, and lots of time wasted trying to decide if it was in the wrong spot, or if I hadnt yet adjusted properly.
also - they aren't really that great I hate to say. after a couple decades of using them I still get the firmware confused by excessive modifier usage and have to jam on all the keys to get it back again (spend a while with a support engineer trying to make it reproducible. they did try, that was something)
the keys don't actually last all that long. they will sell you a new flex/key assembly for the left or the right side though - which is nice...oh yeah, and the function keys stop working pretty quick if you actually use them.
