The Asus VP239H has a maximum contrast ratio of 80000000:1. That's 20% less contrast ratio than a 100000000:1 PC display, which is the most frequently found contrast ratio. Medium monitors that were released in the last year dynamic contrast ratios range from Mega Contrast (worst) to 100000000:1 (best).
It may also be worth also looking at one of the alternative PC displays that have an 80000000:1 dynamic contrast ratio currently available including cheaper flatpanel monitors such as the Viewsonic VX2457MHD (£109.00).
If you would prefer a PC monitor with a higher contrast ratio then you might want to look at the Asus VP278H (£169.99) (100000000:1).