HT all the way.
Haven't found a FS that climbs quicker than my CAAD4 yet. When that day arrivs I'll consider a FS.
More traction on the climbs??!! I think thats a perception. I seem to get loads of traction with my HT. All depends on posture and positioning and gearing.
In the ring that I do most of my climbing in the suspension bobs (middle ring). This gets ebven worse in the smaller ring.
Only FS i've liked thus far for XC are the Scalpel and Epic.