All companies like eVGA, XFX, BFG, etc. overclock thier cards... And they all use the same technology (although some may include thier own memory heatspreaders or an aftermarket fan)... But they are in no way the same. I've owned several graphics cards from several different distributors and all I can say is that hands down, 100%, from now until the end of time, eVGA is the best.
There are a couple reasons why eVGA kicks the ass of any other reseller out there. The cards they sell will probably give you the same performance of any other card by BFG or XFX or whatever but thier tech support and customer service is the best I've ever experienced. And I'm not the only one who feels that way... Goto evga.com and read a little bit on thier forums. Even people who are pissed because thier cards are burnt up have to admit that the customer service rocks. Which brings me to my next point. EVGA has a LIFETIME WARRANTY for all of thier graphics cards... That means that if anything ever goes wrong, they'll replace it with a new one... No questions asked. Another great thing about EVGA is that overclocking your card won't void your warranty. That's right, you can tweak that sucker until your fingers bleed and EVGA will still honor the warranty. AMAZING! Most other companies will void your warranty if they even see a fingerprint on the board. EVGA also has a step-up program. Basically, after you buy your card from them you can send it back for a newer model and only pay the difference...
I recently had to RMA one of my cards to EVGA (damn samsung memory was faulty - not an issue with EVGA but with all 9700GT's)... Well, after filling out the RMA form, EVGA tech support called me! LOL, they called me at home on a Sunday to talk to me about my troubles! That's unheard of from most companies dude. Not only that but after about 15 minutes of trouble shooting they told me that they were going to send me a new card right away... They are paying for shipping of the new card and of the old card. The cool thing is they're letting me keep the old card until I get the new one so I never have to go without a vid card in my rig. It's called cross shipping and I think only EVGA offers that service.
Long story short... EVGA will always take care of you... And they have quality products. Don't listen to anyone who says that all these different companies are the same.
Hope that helps.
Modulus