The Michelins have resulted in positive comments in threads here. I'm a bit tired, but I think they are the LTS M/S. I run the Cross Terrain which is a similar tire as far as I can tell, with more of a road tread design. If you like to off road, then the BFG AT is a heavy favorite.
In my opiinion, more important is to run the same four tires. If you have Bajas on the front then I'd put the same tire on the back.
If you change to the 255, you'll have to get all four tires with a 4x4. Those are my thoughts.