Well, Kinesis Freestyle is definitely one of the better options for split standard layout boards, but if you want something perhaps a little more aesthetic, Mistel has split 60 and split 75 boards, which you didn't mention. These are well regarded, but not as focused on ergonomics.
If you want to focus on relieving wrist tension/stress/pressure to the max, take a look at the Ergodox EZ, and if you like the idea but think the thumb cluster is too far away, take a trip down the rabbit hole at /r/ErgoMechKeyboards to find something a little smaller.