They're just better 'cause they're red-blooded American. /macho Texan voice
Yeah... like NJ5 said, the video standards are the same now. And even before, it was arguable which was better. NTSC frame rate was better than PAL, but the opposite was true of their resolutions. The only reason things generally looked better on NTSC sets was because most content originated in America (film and games) or Japan (games). The games were programmed with the intent of running at NTSC's 29.97, which sometimes cause issues when converted to run on PAL sets. While film actually has a different frame rate than either standard, studios were often lazy and only really put effort into the NTSC conversion, then converted to PAL from there resulting in problems. Any American or Japanese TV show was encoded at 29.97 fps. Because all these things were originally made for NTSC, they also wouldn't really use the added resolution of PAL effectively.
So, the PAL standard was different, not necessarily worse than, NTSC but the most prominent worldwide content originated in NTSC regions, resulting in better general experience for NTSC customers. And it's moot now that we have the HD standards which are the same everywhere.