The viewsonic I wouldn't recommend mostly because TN panels have horrible color contrast and viewing angles. The only real benefit of TN panels are the high refresh rates and pixel response times. But with bad colors you'll sometimes find it hard to be immersed in games.
As for the AOC, it's a really nice IPS panel with 75Hz refresh rate, but as a gamer you should have 144Hz for a nice responsive feel to your games. Only get IPS if you're a content creator who needs perfect colors to edit with.
You'll mostly want to stick with VA type panels because they're color is nearly as good as an IPS and have the same viewing angles unlike a TN, They can also achieve some pretty high refresh rates too unlike an IPS which will cost more to get...