I started with Wierwolf LTs front and rear (they came with a used wheelset that I bought). While they rolled fast, I hated the rear one b/c it would slip anytime I tried to stand and climb, even on the 29er with pretty firm ground.
Switched to and Exiwolf in the rear and have been really happy with it. Lots of good climbing grip and still seems to roll pretty well. Have ridden with it in some varied conditions now, including doing the Downieville Classic this last weekend. Didn't even slip on the steep, shaley climbs or in the mud.
For the front, I was pretty satisfied with the Exiwolf in the rear and the Weirwolf up front when not in the mud. However, the Weirwolf does not work *at all* when it is wet, even when just traversing a mud puddle (in my experience anyway). Since Downieville was going to have muddy sections and I didn't want to worry about sliding out during the race, I race a WTB Motoraptor (29" Motoraptor discontinued, but still available on e-bay and in some bike shops) up front.
Very satisfied with this combination for rocky, wet, and lose conditions, or as an all around setup if you're not worried about carrying a little extra weight in order to have a super durable, grippy, well-performing setup.