I think you should go for the AOC CQ27G2 (27"). It has a 1 ms response time while the ACER has 4ms, it's not a lot but if you really look at it you would see there's a difference. Also, the AOC uses an IPS panel, these are known for good color and viewing angles. Sometimes the blacks can be a bit worse then a VA panel of the Acer. Which isn't great at viewing angles but colors should still be way above average. I think you have to take into consideration: the price, the response time, color and size. I'd go for the AOC, you get a big enough monitor with 144hz, 1ms response time and an IPS panel. Which is really good for gaming for example.