i3 is better.
Another thing to be weary of with the fx-6300 is that most cheap boards wont support any upgraded cpu (at least not properly) and they wont be able to apply the factory overclock well either.
The Pentium is by far the weaker CPU in this mix. Too many people "drinking the kool aid" saying how awesome it is because of its ability to overclock. Yes its single thread performance is great, but at the end of the day the i3 will still win with having double the threads; 4 cars going 80 mph carries more then 2 cars going 120 mph.