buy the cheapest i would say. there are no really bad tft's on the market now (that is if u buy it in the computershop).
only buy a "good" tft when u need it for colorcorrection for video or a calibrated workflow when u prepare printwork or such things...
resolume is fastest when u use 16 bit colors and the framerate is 25 F/sec so a frame is drawn every 4/100 sec and the responsetime of modern tft's are all measured in miliseconds X/1000...