I have a 680 its a beast! I play Crysis 2 on ultra with DX11 and the enhanced graphics patch enabled runs smooth. The card runs at 25 degrees celsius on air in my rig and gets up to 50 after gaming for awhile. This card works great for me. The 560ti-448 used to be the best bang for your buck, but the 680 is by far faster than two 560ti-448s in SLI, runs cooler and uses less power.
$500 for one GPU is never as you say a good bang for the buck LOL 448cores and 560ti is still a better value.