I bought one of these about a month ago, it seemed ok but then started to freeze and stuff, apparently its a common issue with the P5Q series. I RMAd it and they sent me another one (very quickly as well!) with the proper box and everything (B Grade though), havent had a chance to test it yet though.
In my experience with B Grade items, they are usually ok, doesnt really matter about the box as you can download the drivers and stuff, the only annoying thing really is the backplate. I have had about 75% success rate with b-grade motherboards, you have to be careful especially as they usually only have a 14 day warranty so you have to test it thoroughly straight away.
Other B grade stuff if really good IMO, I have bought some cases and monitors, they all came in their original boxes and accessories and were in perfect condition (got my cosmos s for £80!).
BTW they have "10+" 4850 1GBs on there for £103 each, looks like a pretty good deal!