Hi Zilliak,
for many games you will not notice much of a difference, however as more and more games will take advantage of more than two cores, get the 720 for $18 more.
Actually the difference between 2 and 3 cores is larger than the difference between 3 and 4. The reason being is because when you game, most games only use 2 cores, if thats all you have, those 2 cores run the games and everything else. But if you have 3, your games have 2 and everything else has 1.
I too highly suggest the 720 BE, I have it and love it. As far as OCing better, maybe slightly, but it isn't going to make up that extra cores performance for your other tasks to use.
I too highly suggest the 720 BE, I have it and love it.