I have a leap v2 refurbished by Crandall . They put a bit more padding in the seat and back and cover it with very nice fabric.

I think the current thinking is that ergonomic chairs should encourage a variety of postures and that is why I love this chair so much. I am 6'3 and use the chair in many positions. Back locked up,back tilted back, sitting on the edge, sitting all the way back.

A chair will not help an injury but I think the steelcase leap/Amia and other top models are the best office chairs ever. I don't like the aeron as much myself.