Wore these on a rocky 12-mile loop and the grip held up great on wet roots and loose gravel. They're light enough that my legs didn't feel wrecked by the end, and the fit stayed snug without pinching.
The lightweight feel is what sold me — my feet didn't feel dragged down even on the long climbs. Grip is solid on loose dirt, though I did slip a little on wet roots, so keep that in mind.