The XZ350CU has a maximum contrast ratio of 100000000:1. That's over twenty times the contrast ratio of a 5000000:1 PC screen, which is the most common contrast ratio.
A 100000000:1 dynamic contrast ratio is in fact the best contrast ratio amongst all similar spec LCD screens that are a comparable age to the XZ350CU.
The worst contrast ratio amongst similar types of PC screen is Mega Contrast.
There are a number of alternative flatpanel monitors that have a 100000000:1 dynamic contrast ratio currently available which you might want to look at including the H277HU, or the G257HU ($221.99) both from Acer which has a better Rating.