Was thinking of getting a second 780 or getting a 980. I haven't had any experience with SLI and was wondering if there was any problems with SLI technology. I can get a second 780 for about $350 on amazon whereas the 980 is about $560 or so. Fairly certain that I can't sell the 780 because I'm sure many people are scrambling to sell theirs. If you had the money to do either choice which one would you choose?