The numbers expressed in milliseconds are pixel response rates. That is not the refresh rate, which represents how frequently the screen is redrawn, but the time it takes the single pixel to respond with a color change. Faster rates reduce blurring on fast motion video. Five ms is pretty fast, and unless you are watching fast moving movies or games with high contrast scenes even slower responses are fine. Most newer monitors tend to have the fast times, and 5 ms is getting to be the standard.