Would this be a good GPU to buy?

What I would be concerned about is that if anything does go wrong with the card within the "warranty" period, and this seller is no longer around (311 feedbacks even at 100% is dubious at best), then you will be stuck with a bad card.

IMHO, sometimes it is better to spend a bit extra for a known product from a reputable seller. You might save yourself some headaches. There are several new, retail boxed, "buy it now" 6850s on the UK e-bay site right now that are in that price range that, IMHO, would be safer buys.

you can get a 6870 in box, new and with shogun and some other games for $150 Cad. Not worth it bud, dont buy it, its way too risky.