First paragraph is only back story in the event my the community thinks my troubles might hold some leverage. Feel free to skip it if you want.
I recently developed a problem where I couldn't use my PC is it was right side up. I diagnosed the problem down to BOTH my GTX 460s. MSI was satisfied with my troubleshooting and allowed me to replace my cards one at a time since I could still get some functionality if my PC was on its side. I was originally offered a 650 for the first 460, but when I explained that I used SLI and the 650 does not support it, the tech agreed with me then promptly stopped responding for 2 weeks. I picked up discussions again and was told that my warranty had expired now (by 2 days) and nothing further would happen. I told them this was not kosher since they'd had my card in hand for very nearly 6 weeks and it had been nearly a month since the first tech asked to replace the card.
Now, they have replied offering me one GTX 660 in exchange for both of my 460s. I have done some digging on my own and it seems that the single card might be a slight downgrade according to some forums and I also found this website that attempts to compare video card setups. It gives 2 categories to the GTX 460 SLI and 2 to the 660.
I'm wondering you guys' opinion on if this is a side or upgrade and if you think asking for either a 660ti or a stock 760 would be acceptable from my position considering the waiting game and then telling me I would get nothing.
that being said you ciuld always ask if they would have a 660ti laying around...just in case and see what is their answer...but i would pick the 660 and try to find a cheap used 660 later on to sli them...