I have run several Ultegra and DA BB. The Ultegra is the way to go, unless you enjoy doing service. If you do enjoy servicing your bike, buy the DA. Get a tube of high quality grease, learn how to adjust bearings, and feel the added smoothness.

That being said, my fiance's bike has the Ultegra, and this one BB is freakishly smooth. I have never seen anthing like it. Sometimes, you just get lucky.