I would advise against Viotek, as I have never heard of it and the google search didn't come up with Viotek's website(if they have one).
AOC, on the other hand, is a well known monitor company and I think you should go for that one.
Also, the Viotek uses a VA panel, which tries to combine the gains of both TN and IPS, but fails miserably in my opinion. It's refresh rates are good on paper, but when going from dark to dark, the ms grows quite a bit.