GTX680-DC2-4GD5 VS N680GTX Twin Frozr 4GD5/OC

For that you don't need 4GB card, a standard 2GB for those two models will do, in terms of preferences, the asus has a good cooler, the best in the acoustics department, the msi twinfrozr, though also as a good cooler, offering low temperatures.
If you want value, $/performance, a 670 gtx is better, those two models also are present in that card.