I ran BFG MT 33x10.50's for a year and a half before switching to GY MTR 35x12.50's.
As everyone's mentioned so far, the 10.50's were really nice on the street, and the only place they only worked OK was in sand.
Sometimes it would have been nice to have the wider track that the 12.50's give you, but not often.
If you do a lot more street driving than off road, I think you may be happier with the 10.50's (unless you do a lot of sand).
4" Currie springs/CA's, TR beadlocks, 35" MTR's, D44's ARB's & 4.27's, RCV & Superior, OR241, UCF TT