OP you'll be fine with either card. I originally had a 6870 that I sold to upgrade to the 570, which I then Stepped Up to a 580 and to be honest I haven't thought of looking back. The 580 runs the same OCs at the same temps or lower all while producing a good FPS more.
I find it weird that my SINGLE 580 wasn't any hotter than my single 570 and in some cases it was cooler while needing more volts for the same OC. I chalk it up to a better vapor chamber as someone has mentioned it is slightly modified in order to allow more volume if I'm not mistaken.
Originally Posted by Fateful_Ikkou
You underestimate the 560's power but if your going to get a GTX570 check this link if you plan to Overclock it: LINK
With my two regular GTX560s I can run Crysis 2 maxed out with the DX11 Tessellation Patch and High Resolutions Patch. I maintain 60 FPS throughout 97% of that game with those settings.
Here we go again with someone trying to justify their lower end purchase by claiming all 570s are junk.
Keep in mind most of the cards were from one vendor which could relay the fact that they might have just been a bad batch.
Before copy and pasting that link all over the place perhaps you should read the whole thread. Hell even look at the new name of the thread, you know where it says "No recent deaths, buy some 570's"?