From personal experience and as a mechanic I think they are pretty reliable cranks in the mid-price bracket. They keep their appearance better than the Shimano alternatives and the rings last loger, but the bearings are even more rubbish than Shimano.
Careful fitting is paramount. You must face the BB and use real force to bottom out the splines on the first fitting. I use a 2ft breaker-bar to do this!
I recommend the Hope Stainless BB's having tried Acros SS & Superstar. The only original fit system to come close is the Truvative GXP, but they're not compatible.
If you wear your rings fast, buy the RaceFace, otherwise use Shimano or Truvative, but be prepared to buy Hope BB's
PS. I am using a Deus set on one bike and a Bontrager Carbon (Truvative GXP) on the other. Campag have the best design, but that's on my road bike!