I think SFA's are overrated. I know, I know. I love my IFS and I'm very biased. It rides great down the road, its very safe and has decent flex once the sway is disconnected. Plus, there is no danger of death wobbles. Every single SFA vehicle I have owned has experienced this one time or another.
Ok so the Nissan IFS is weak, everybody knows that. Toyota's have a much better track record, probably the best. Fords TTB just plain sucks and S-10 CV's must have been pulled from a Chevette or something. A few upgrades and the Nissan can be very reliable with 35"+.
If a SFA truck had good travel (AKA F150 Raptor) it would win in every category vs. SFA IMO. SFA's don't allow the tire surface to travel paralell to the road surface. OK so it looks cool while the front axle is all twisted up on a big hairy rock. Give a IFS good travel, lock it and some really robust arms/joints and you'll have a serious contender on your hands.
I predict in the next 2 years the world of rock crawling will see a lean towards IFS as the geometry is so much better than a SFA. Look for the a-arms to attach to points very close to the centerline of the vehicle and a lot utilizing a pumpkin similar to a Z32 rear. More tire contact, more traction, more everything... except weight.
I am not a professional rock crawler, just my personal experiences with SFA's and IFS.