I switched from the Evo to the Kestrel last season. My very first impression was that the Evo was more comfortable but I soon figured out through both this site and trial-and-error that the Kestrel has to be used a little differently. Once I found the sweet spot and proved that I could do an all-day sit in the Kestrel, I sold my Evo because the smaller size and lighter weight were big benefits to me.
All that said, I would love to try the Kite or Mantis as they both seem like they could be even more comfortable than the Kestrel because of the way they form a cup for your seat.