Crank Bros Cobalt Wheelset

So I've been dreaming about a new wheelset for quite a while now.  One of the kids up here at college rides for a Crank Bro's team and is looking to unload a pair of his Cobalt's as the new bike for the season is coming with a new pair.  Wants $550 (retail is $950) which is reasonable.

BUT I've heard some issues with rear hub reliability.  And I'm getting mixed reviews on how strong they are.  Mostly technical trail up here with the occasional epic mountain runs, but I've been known to do 30 ft. building drops during finals week :ihih:  And he's willing to do the "poor-college-kid-monthly-payment" dealio...that's a big deal for a ramen-eating dirt-covered college trail junkie.  Opinions?