It actually *is* about a ten minute walk to the city centre. However that is where the shops are. Bars / restaurants etc are actually closer than that - just a brief walk down Ormeau Avenue. The Radisson is not in a bad location at all.

Belfast is the second safest industrialised city in the world (after Tokyo) apparently and I would have no problems walking about at night. There is some public housing on either side of the hotel which could be considered less safe but you have no need to walk through it and 'less safe' is relative - it just means that they arent used to tourists walking through the middle !