~8ms is 5 times as sharp as ~20ms but the price is 2x - 3x, as far as drawing charts they look the same unless you also use it to watch other stuffs.
For now, it's better to trust your eyes. "Your average user running standard applications on an LCD monitor is not going to notice a difference between 12ms and 4ms, even assuming those are using the same criteria. Gamers and high-performance users will definitely notice," says ISuppli's Alexander. But "25ms to 30ms is fine for most business applications, unless you're in an application that requires a lot of scrolling." -net