Just be sure - it's not a younger kids show anymore.
This version of Thundercats is, to say it right off the bat, fantastic. I never thought I'd see animation this detailed, fast and realistic on Cartoon Network, let alone this amount of maturity and violence that gives this show a definitive "Teens and up" age grade. Not that it's very violent for younger kids, because it isn't all that much, but id does have some on-screen deaths and the story is pretty deep for them to understand. Also, as some reviewers before me stated, the character Cheetara is clearly made to look sexy and is in a pretty revealing outfit. Of course, pretty much all anime-watching teens love a little bit of fanservice, so there's nothing really wrong with that.
Believe me - you won't be disappointed with this show. It's right up there with Avater -The Last Airbender in terms of quality, animation and action. Go watch it! (although there are only 2 episodes out for now...)
What other families should know
Great role models
Too much violence
Too much sex