The AOC has a higher brightness and contrast ratio being an IPS (250cd/m² vs. 200cd/m², 1,000:1 vs. 600:1 respectively). I would go IPS over TN every time unless going for a high speed monitor. The IPS also has a much wider viewing angle (178º vs. 90º). For the same price, it's a no-brainer to go with the AOC.
Regarding overclocking it, with a monitor it's a gamble. You may, or may not be able to overclock it without coming into problems like stuttering in games. It depends on the internal components. I've had some monitors that overclocked to 90Hz that ran smooth as silk, and others that overclocked to only 75Hz that were terrible and gave in-game stuttering causing me to return back to 60Hz.