This has to be one of my top animes of all time. Planetes is a hard sciencefiction story with incredible characters and a great view of the future. While not everyone will be able to appreciate this, the show after watching so many shonen animes was a breathe of fresh air. It was refreshing to see realistic character interactions and well developed drama as well as a believable story set in space without huge robots and explosions (sorry Gundam, you're still in my top animes too!)
If you live more mature stories, if you are really anal about characters and their interactions then you'll love this show. If you really don't give a shit and watch animes for the action or boobs, then you probably won't enjoy it.
10/10, would buy on blu-ray and watch again.