really is hard to go wrong with a un53 i have had a couple go south on me in a year or so but also had some that seem to last just about forever.

i'd say the only reason to go for something more expensive is if your looking to save some weight or if you need a dead reliable bike for a trip across continental asia or some such nonsense. and then i'd still only really trust shimano or the ridiculously expensive phil wood. i am sure other companies make good bb's but i don't have any experience with them.