I am personally a fan of buying two of the 2nd best cards for SLI or Xfire rather than teh best single card in a line-up. But I've already made the investments involved with multi-gpu in mind, such as a motherboard with two full slots between cards, a well-ventilated case, a PSU with the right amount of power/connections for this kind of setup, etc.
I've also already been through the 'learning curve' involved with multi-gpu. It is true that it is not as 'trouble-free' as a single card setup, but in most cases, issues can be fixed through one means or another ... but until you figure out ways of doing so, it can be a little (or even a lot
So I guess what I'm saying is that while SLI 570's are clearly the more powerful setup, and probably are a similar better bang-for-buck value, there are some 'hidden costs' beyond just the price difference (i.e. more expensive PSU and motherboard, and possibly case, addt'l heat/noise/power consumption, plus hassles that involve investing time/learning) that you should consider as part of your calculations as well.Edited by brettjv - 12/26/10 at 9:16am