Firefly vs. Cowboy Bebop

Amongst all the things I've seen and read about the unfortunately short-lived tv series Firefly, I don't think I've managed to find anything speaking to the similarity between Firefly and Cowboy Bebop. How is this possible? I might have missed, but I don't think so. How can two shows, regardless of their obvious difference (anime vs. live action) be so incredibly similar, yet have not a single comment about it?
So the Firefly crew is bigger, but the character-base is very similar and the premise, locales and setting is very close too.
One of the few basic differences is that Cowboy Bebop wasn't canceled, although it was put on a short hiatus in Japan when it was considered too violent for a time.
Anybody?
Thoughts?