I'd get the less expensive one. In all likelihood, it overclocks well, close to, matching, or exceeding the factory overclock of the other model. Even if it doesn't reach it, the performance gains could quite minimal from game to game.
I'm a huge fan of EVGA these days. They RMA'd, free of charge, a gpu I broke. I explained exactly how I broke it, provided pictures of the damage, and everything. I love 'em.
Sorry, I don't mean to sound like a commercial or anything, but the company really did a nice thing for me, so I have to share.