The one on my KX defenatly isn't soft. It was almost as hard as a KTM seat when new. Now that the hassle of getting it is over (took about 6 months) it's been a great seat. It isn't much taller than the stocker. Maybe 1".
I got a One Industries complete seat for my CR. Just the standard height. I was pretty happy with it, although I had to modify the mounting brackets a little to get it to fit good. I drilled the holes just slightly bigger, and loosened the nuts and re-tightened them until I got them in a better position. I think the One Industries seat, is really an SDG base with their seat cover, I'm not really sure.
I have a SDG tall seat for my RM..... Love it, great firmness and comfort. It's about 1-1 1/2 taller than stock. I highly recommend one. People that take my bike for a spin always comment on how they love the seat.