I don't know why it's so highly rated by people since some episodes aren't that good. I mean if you ever watched Battlestar Galactica , Smallville or Dr. Who I never remember seeing a bad episode or one that made me want to watch stopping future episodes. Hero's also started off good like Lost. First 2 seasons really good and kept you interested then started getting repetitive and dumb,etc.
Then again maybe it just depends on the person's taste?