Well, the wheels are light and hold up well as long as you stick to cross country type riding and don't make any major mistakes. I started night riding (w/ lights) with a group a few weeks ago, I'm finding that it's hard on equipment as I'm hitting things that I normally wouldn't. Last Wednesday night, I hit something (most likely a rock) on a descent, never saw it, it kicked the rear end up and to the right. I was just happy not to eat it. It bent the rear rim pretty bad, it was what some call taco-ed but I think potato chipped is more accurate. The tire wasn't hitting the frame so I finished the ride back. The nature of the bend was such that I couldn't tell what was straight and what was bent, so I decided not to attempt to straighten it myself and got a couple of recommendation for wheel builders (or straighteners in this case) in the Asheville area. I went to the first guy and after a day and a half wait, he said he couldn't do anything with it. Based on the my reference (because I was told if he couldn't fix it, it wasn't fixable), I was shopping for a new wheel set but before I pulled the trigger, I checked with the second reference. He was amazing, in less that 15 minutes, with me watching, he trued that wheel to the point that it was probably straighter than when it came out of the box. He wanted next to nothing for doing it, so I bought a few extra items while I was there (Stoked on the great service). The place is Biowheel in downtown Asheville, great service. Anyway, I took the bike out today for a normal ride, several steep descents with rocks, a few small jumps and the rear wheel is still true. I'm going to be looking for a new sturdier wheel set but at least now I can do it when I'm ready and not rush it. Biowheel is now my LBS and I hope to give them my business for the new wheel set.
But back to the issue, yes the wheels are fine but if you start getting aggressive and hit something you shouldn't, you may have problems. Now, I'm sure that true with a lot of wheel sets. I haven't had enough to experience to really make a fair comparison with other wheel sets.