You can mostly ignore the numbers they publish. The response time and contrast ratio can mean just about anything.

Look at reviews and user opinion threads like
this one. That Acer is definitely better than the other one, but is still a basic TN and would be inferior to the ones I mentioned earlier.
As I said earlier, the monitor is the one thing you don't want to go cheap on. It's arguably the most important part of a PC. I would suggest getting a cheaper case and motherboard to have about $300 left for the monitor, which will give you a lot more options.