It's a super-stuffed sci-fi anime that goes full throttle and doesn't stop, no unentertaining filler in sight. I haven't read the manga, so I can't comment on it, but I bet it's even better than the anime. It's not a show that's always light-hearted, since there tend to be dark moments scattered throughout. I'm a huge fan for space cartoons, and this is top on my list. The only complaint I have would be the abuse and fan service specifically targeted towards women. That type of stuff is becoming a huge problem in modern-day society, especially in anime. Even with that said, I still really enjoy it if you can look past that, which I know is hard for some people. Hopefully the second season for the anime adaptation will be even better than the first!
