I can't remember where now, but I remember some hub instruction saying that the seals will break in and loosen up with time. I would have left them on for a few weeks of riding, then see if the wheels still spin noticeably smoother without them.
There are no "real" sealed bearings. Bearings are moving parts, so either you have something rubbing or you have an opening. Do you mean cartridge bearings? Those aren't necessarily better than having the races built into the hub.
Last edited by CaptainCool; 10-20-09 at 05:40 PM.