Depending on where you live, the difference is like $20. If money is no option, I would recommend you get the OC version. It's awesome. My particular sample boosts 2025MHz without user intervention. 🙂
They're the same, except that one is guaranteed OC at a certain clock speed. If you buy the standard, there are no guarantees that you'll get the same overclocked clocked speed. If i were you, I'd buy the OC version.