I bought a pair of these after really digging the Atom short sleeve jersey. I would class these as XC shorts, mostly because they are very lightweight. Not necessarily fragile, but they are pretty flimsy compared to my Fox Sergeant shorts, which are my current favorites. I am mostly an AM rider, but I do roll XC and commute by bike about 35 miles a day on workdays.
These are lighter and cooler than the Sergeants, but the Sergeants are light and cool enough for me, and they are more brush-resistant and sturdy. When I drop my phone in the thigh pocket on these, it moves around a bit and I can feel it through the fabric, whereas the Sergeants hold my phone firmly and I can't feel it the same way.
These are also longer than any of my other shorts, so be prepared for that look. They fit true to size, I wear a 34 in these and my other shorts. These are loose enough for comfort and movement, but they don't get caught on the seat or anything.
All said, I like these shorts, but they don't see as much action as the Sergeants, and when I went to order another pair of shorts last week, I went with another pair of the Sergeants. Fall is here and I'm not as concerned about heat, and I just like the Fox shorts better right now, paired with an Atom jersey.