I'd stay away from Full Ceramic Bearings (even good quality). It's not a good match with MTB because of the repeated shocks they will see (and they are very expensive too).
I'd stay away from Hybrid Ceramic Bearings (even good quality). Same as above + they WILL rust in no time. The balls are Nitride but the rest is rusting steel, and will rust.
I'd stay away from CHEAP Ceramic bearings like hell. It's not a good match for... everything.
My recommendation, if you want quality bearings, is SKF bearings. These are steel, high quality, not cheap (x2 to x3 vs. cheap ones) but they are great quality (very strong, well sealed, high precision, nicely lubricated). They are still cheap enough that you can replace them when you need.
EDIT: I forgot to mention that you don't buy specific hubs because they come with the bearings you want. Just buy hubs that you like and can afford. Then replace the bearings when they are worn out. It's always pretty standard sizes.
EDIT: Reading your message again, I get the feeling that your message is just advertising for this company... I could be wrong but something tells me that I'm wasting my time here. Anyway, my advice might help anyone with the same question!
