Heroes always look fantastic to me and in 5.1 (OTA). But then our local NBC actually spends money on their HD signal to make it the best they can. Heck, they even bought equipment so that they can do weater statements and school closing inline the HD signal so they can provide that service without dropping out of HD. Very nice.
Still, it's not the best for sports.
Many NBC's are "questionable" in particular with sports because NBC is 1080i and many of the local affilitates do several subchannels which starves that 1080i HD stream to the brink. My local CBS has this problem, NBC not quite so much.