I had it narrowed down to the spongy wonder and the spiderflex. I went with the spongy wonder because of the ability to adjust the width between the pads. After getting it set up it didn't seem to be much of a factor so I think that either seat would work.
I tried the Hobson easy seat - and didn't really like the fact it rocked - it was comfortable it just felt weird. I also used The Seat for a bit, which seemed to apply more pressure where I did not want it.