Yukon chromos with Spicer 760 joints. I've broken a long side inner, a stub shaft, and wasted the passenger side shafts/joints. I attribute the last one to a lesser joint though (Alloy USA X-joint. The 760's haven't failed me yet).
It depends entirely on driving style though. I wouldn't expect the front end to hold up if I was a throttle jockey. I crawl everything if I can. If not, I'm not afraid to give it the necessary throttle to get up an obstacle, but I'm not going to bounce it off the rev limiter trying to make a climb. If it takes that much, I have an inadequate vehicle for that obstacle.
Looking back, they've treated me well, but I wouldn't mind having a set of RCV's. They'd be smoother ,stronger, and I wouldn't even carry spares. I keep a complete set of replacement front shafts with me when I go on long trips.