Well, PAL systems run at 50Hz (50fps) while NTSC runs at 60Hz. (~60fps) NTSC is smoother, although PAL has better color handling and higher resolution (625 lines on screen with PAL, 525 lines with NTSC. Most people prefer NTSC simply because it runs faster. Older PAL TVs can't output 60Hz NTSC signal, so you'll either lose color or lose the entire picture if one's TV isn't NTSC compatible. Of course, from an emulation point of view, PC monitors display NTSC and PAL without a hitch, plus you won't see any differences in color.