The GTX 570 HD is a fail. Radial heatsink technology on a card with 480 CUDA does not sound like a good idea to me. Not to mention the fact that it's a non-reference design that they are making you pay more for a lifetime warranty. Non-reference also means that you will not be able to get aftermarket waterblocks on it, unless of course eVGA decides to make one for the second in command card, which let's face it, won't happen.
OP just so you know there is no difference between the GTX 580 SC and the GTX 580 BlOps edition other than aesthetics.
Also you cannot step up to any card other than the reference GTX 580. I had a similar question for eVGA via email and they said that they can only step up to regular 580.
The Step Up program is limited to the reference model of the graphics card as the yield of factory overclocked cards can vary and is not consistent. Unfortunately at this time, only the reference model is available for the GTX580. Regards, EVGA
As far as I can tell there is no difference in the binning process of current Nvidia/ eVGA video cards and the SC version relies solely on it's measly overclock to justify another $10-$20 premium.
Hope that helped answer your question.