I have a set of wheels from them. They work fine. Be aware, the the wheels do not have an internal spacer to keep the smaller inner race from side loading. So if you do install it, make sure not to cinch the nuts to tightly. The wheel should spin freely as well as the outer race, while the inner race is immobile.
The plastic seals are fine as they are essentially impregnable. I'm wet grinding and its seem to work just fine.