Actually, The 4400 reminds me of this series of novels published in the 80s and 90s called Wild Cards. But that's beside the point. Both Heroes and The 4400 are superhero fiction, and, as such, will have superficially similar characters -- there are only so many superpowers one can come up with -- but they have different focuses. Heroes' focus is about the struggle to save the world, whereas The 4400 is about the struggle to be accepted. Both are interesting, but in vastly different ways. I'd hope that we'll see more about the acceptance part in Heroes at some later date, especially given the "future" episode of Heroes.