Answer: the one that fit's you the best. I use a seat harness, a cheapo Cabrihna, tried everything they had in the store when I purchased it, and it fit the best. Most comment's I've heard from other kiters in reference to the harness I use is,"those ones are crap".
Horses for courses, try them all.
To be contradictious, I've heard Mystic are pretty good
.