The highest contrast ratio of the Hanns.G HS221 is 80000000:1. That's over four times the contrast ratio of the most common dynamic contrast ratio of 20000000:1. The worst contrast ratio of all medium monitors that have been on the market for more than two years is Mega Contrast and the best is 100000000:1.
There are a number of other LCD screens that have an 80000000:1 dynamic contrast ratio currently available that you might want to look at including cheaper flatpanel monitors such as the HL226HPB (£88.99), or the HS221HPB (£85.90) both from Hannspree or the Asus VE228 (£79.98).
If the contrast ratio of this Hanns.G flatpanel monitor is not high enough for you then you might also want to look at the Acer 222HQL (100000000:1 and cheaper); or the Acer G237HL (£101.98) (100000000:1 and higher rated).