I'd vote for the Bontrage Mustang. I'm running one right now on the rear, got it because the shop didn't have any Sun rims in stock. I'd also recommend the Sun CR18 - my personal choice for strength, value, and weight. In my experience, Sun rims far outlast Mavic rims and cost a lot less. I prefer the "triple box" construction. They only weigh slightly more than some of the other XC designs but they are a lot stronger