I put a stone through one in Wales last year, and when I when to have it repaired, the shop said that they saw quite a lot of XP2000 with similar damage - they're not really tough enough for off road use.
I only had one on one corner (emergency purchase after a puncture on Christmas eve) so I can't really comment on performance wrt. grip etc.
Oh, and it wasn't repairable either.
Alaric.