Yes and no. You can't really get any OC on an i5-3470. I mean, you might be able to get .4 ghz or something, but its generally not worth buying a board capable of doing that. And yes, the fx-6300 will "beat" the i5-3470 in many applications when overclocked, most of them multithreaded. But for gaming, the overclocked fx-6300 generally only "beats" the i5-3470 in games where processor is largely irrelevant - real world performance will be the same. And the i5-3470 still has an advantage in some games like the Total War series, where Ivy Bridge currently destroys all competitors (including sandy bridge!).
But that's not really the point. the fx-6300 is a fine chip, and if you go to the trouble of overclocking it, it's roughly the same performance tier as an i5-3470 and a great choice. The bigger deal is that if you DON'T overclock the fx-6300, it is notably inferior to the fx-6300.
The OP did not specify if he planned to overclock (and no, even here this cannot be taken for granted). If the answer to that is no, the i5-3470 is a clear winner.