Bearings do tend to break in when new. Friction should reduce for a while. Hard to tell whether the new one will ever reach a point where it spins as smoothly as the old one, but not a huge worry.
For the frequency of BB replacement I experience, I typically spring for the un54 for bikes I'm going to keep.
Last edited by LesterOfPuppets; 09-04-10 at 05:53 AM.