Hmm, while I was setting it up I had it plugged into my montor and regularly switched between it and my main machine which has a 6870 in it and there wasn't any difference in quality, least not enough for me to notice. Only thing I have done is install the latest catalyst drivers and set the correct overscan for each resoluion/refresh rate.
As for gaming in general its not bad at all, you can play most things at what I would call console level detail, performance is very much linked to memory speed, it helps a lot that I have my ram at 2100Mhz+. Still at stock it would play eve online with playable frame rates no issue.