I've bought three sets of Zerolights from Nashbar, although they have been 26" MTB wheels for flip bikes, and every set has been a great value. No problems. I took one set off the Craiglist bike and use them on my new commuter. Smooth and true.

The set from Nashbar for singlespeeds is almost a pound lighter than the Weinmanns. The Weinmann wheels might be better...............but from my limited experience with only three sets, the Zerolights are a hard bargain to beat.

I don't know if either comes with sealed bearings or not.............and I don't care. There were several bikes sold that went a few miles before sealed bearings were even available. Service the things and go. No big deal.