They have stock WC blocks so I don't have to go buy / build my own and their factory OC'd so another step I don't need to bother with.
My question is, typically Nvidia goes out with a mid series "upgrade" to the silicon. 280 > 285 type stuff. These card's are not exactly cheap and represent a multi-year investment. Would it be wise to wait longer, is Nvidia going to do another silicon update that's usually cooling / faster? Or just toss in and use them for the next 2~3 years.
Two GTX 580's will last you for a few years regardless of any updates. Supposedly, Kepler is going to hit the shelves next year but I am in the same boat as you. If there are good deals on a GTX 580 for Black Friday then I am just going to pull the trigger on one of those because to be honest, I personally do not believe Kepler will be mature enough until later next year.
I have been thinking about it a lot and have some personal educated opinions. I believe that the higher end Kepler cards will be out sometime in the summer which means that there will be some nice iterations of the 28nm process by the end of next year. Having said that, 2 GTX 580's should outperform every single GPU Kepler card, maybe besides a dual GPU card (GTX 690?) and higher end SLi variations (GTX 680 SLi / GTX 670 SLi?).