The 7850 at reference speeds and on the release drivers isn't that impressive next to a 560 ti 448 or 570, but the higher clocked non-reference versions together with later drivers (which are massively improved for the 7000 series) come out overall better I think. Plus it'll be suited to newer games that use more memory and tessellation.
This is what I was thinking,as a 570 is as good as its ever going to be whereas the 7850 can only get better (I hope). Also the fact that I may be able to crossfire it if I up my resolution.
Bought the asus 2gb 7850 dc2 in the end, and it manages to max out every game I own at full HD. Its also very cool and quiet.
Have you tried to OC it yet. Mine is at 1000mhz and runs great. Glad you happy with it, its a good buy.
Don't really think theres any point a the moment, as it runs every game fine and it is factory over clocked (only a small one admittedly). Once it starts to struggle I might as I have seen that it over clocks well. Good thing I didn't get the 570 though as the 7850 only just fits in