obviously, the resolution is important. but a preference thing.
the most important monitor specs are response time (2ms ideally, but no more than 5, and it needs to be measured white to white, not grey to grey) refresh rate (60 is normal, but 120 would be great) and contrast ratio (the higher the better, but if its dynamic, you can pretty much ignore the number they give you.
basically, just look at some monitors in your price range at the desired resolution, and compare the w2w/b2b response time, contrast ratio, and refresh rate.
We have a lot of Dell computers in our offices with all different sizes of monitors. I am not sure if any of our monitors are the exact model you are picking out, but I can tell you that I am not impressed with them. At all. Period. In fact, if I ever buy anymore Dell systems, I am ordering the PC's only, they can keep their monitors. We have a few $159 Viewsonic monitors scatter around that we have bought as replacements, that put the Dells to shame.
The only monitor recommendation I can really make is the Asus VW246H or the VK246H. Both are the same monitor, but the VK has a built-in webcam. I bought the VK246H 'cause it was on sale and I wanted something to monitor some processes on my HTPC.
Here's a link to the VW246H, it appears the VK version is not in stock / temporarily delisted: