I've owned 4 EVGA GPUs, and one motherboard. The GPUs were great, cant say anything bad about them (maybe they ran a bit hot but they never died on me). The motherboard, on the other hand, i've had nothing but problems with. My 680i had problems with the network and RAID controller, that even flashing the BIOS didn't help. It was always a pain to get an ethernet connection working, even before the network controller quit on me. I have two friends who have had issues with 780i also.These problems with the motherboards are not so much the fault of EVGA as they are of Nvidia though, they just seems to have bad mobo chipsets (generally speaking) from my experience. x58 is an Intel chipset so EVGA has that on their side at least, but man did they ever overprice the $hit out of it.
As far as customer service, I've never personally dealt with them, however, i have a friend who has gone through a couple GTX260s (ruined the HSF trying to remove it on the 1st, over volted the 2nd one.) and he had replacements no problem. I also heard great things about their upgrade program, you send them your old GPU and they give you a discount on a newer model, but i hear all of them are actually factory refurbished (but who cares as long as they work), oh ya they make you pay shipping to an fro too. Not sure how useful the upgrade program is though, you could do better by selling your old card on kijiji or something. Anyway, thats my 2 cents on EVGA :P.
Edit: I agree about getting rid of one of your GPUs, way overkill. Go with a higher end single GPU, then SLI or Xfire latter if you want.
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