AMD total $193.97
Intel
Intel Total $278.97
Both systems when upgraded with a GTX 660 card ($219.99) will play pretty much everything at 60fps+.
Personally I have a FX-6100 + Radeon 7850(about the same price point as the 660) and BF3, Crysis 2, Spec Ops The Line, Assasians Creed series all play minimum 60 fps across the board, buttery smooth. The Intel rig might hit 80fps but if you were to put the two systems side by side would you be able to take "the Pepsi Challenge" and tell the difference? No, they both run at the monitors refresh rate, unless your monitor is 120Hz at which point the Intel system won't be able to hit 120Hz anyway.
But as far as the $300 vs $500 price point most of the cost is a decent mother board but overall I was shooting for Big Box store prices and mid-upper level main boards which for AMD systems would be a better investment anyway since an AM3+ board will still still be good for 2 future generations where the Intel board is already dead in the water.
Testing can show the presense of bugs, but not their absence. -- Dijkstra