Got a Galaxy SII from them when it came out last year (on a whim, they had the best price plan, seemed like a good deal). Got it home - no service. Left it a couple of days thinking I hadn't been connected yet - took it with me when I saw a mate in Eastleigh and it woke up. Went home and....dead. I found blackspots (no signal what so ever) all over Bishopstoke and the back end of Fair Oak. Dunno if this affects you but thought it was worth sharing.
When I tried to take it back to the three store in Southampton they gave me the run around big time. Had to go in on 3 separate occasions while someone somewhere faffed around. Their excuse was that "there aren't any blackspots on our map in your area, go home and try again". I think they were just trying to push me past the 14 day return policy, eventually I just refused to leave the shop til' they ended the contract.