evga has the same warrenty
Like PP said though, BFG just boasts about their pre-OC'd cards...now granted, they will do better against a stock card because obviously it has a SLIGHT edge, but you might notice 1-3 FPS gain in an actual game.
My eVGA 6800GT is stock 350/1000 and I've OC'd it to 450/1200
the memory I believe maxes out at around 1210-1220 for me, and I haven't maxed out the GPU yet...I think it can hit around 455....my point is eVGA makes really good quality cards assuming you cool it adequately in terms of wanting to get those high clocks.
I believe they use japanese capacitors on their cards, which are basically number 1 in the world as far as capacitors are concerned. "Arent they all the same?" no they aren't...cheap ones will be prone to die easily and might not hold a stable voltage through em.
Quality parts = quality card = longer life and overclockability.
This isn't to say BFG is bad, by all means I haven't heard anything bad about them really, but me as well as quite a few other people can vouche for eVGA being quite good