The 670 is a superb card, even a reference card has a fairly quiet stock cooler with plenty of overclocking headroom.
The amd drivers have caught up for sure with games like BF3 etc, but IMO it always seems to take them a while to get them upto scratch with some of games. Latest drivers anything 7870 and up is worth considering.
One//i5 3570K 4.5Ghz//Z68X-UD4-B3//8gb DDR3//2 x GTX 670 SLI// HX850W//CM690ii//2x128 V200 SSD//Xonar DG//
Two//i5 3570K 4.7Ghz//Z68P-DS3//8gb DDR3//GTX 460 SOC//XFX 450W//Akasa Mirage//128 840 SSD//Xonar DG//
Three//FX8350 4.5GHZ//Asus M5A99X EVO//8gb DDR3//HD7870//TX850W//120gb 840 SSD//Xonar DG//