Todays response times are based on no standard anyways, so you cannot really judge a monitor unless you know how they test the responsive times on this said monitor. My 12ms tft is for example faster than most 8ms, because most 8ms monitors are tested just using picture change algorithems that are easiest.
A 12ms monitor can often be no faster than a 24ms monitor that is tested properly.
Something you also need to know, is that great responsive times also often mean less perfomance on other areas. A 8ms monitor usually have more problems with contrast and colour gradiation than a 16ms.
My tip is to test the monitors yourself at the store. Simple test like moving around windows, mouse pointer and such can actually show big differences between monitors.