Already watched both seasons. First season was a bit better than the second if only for a certain scene, but they were both pretty good. I have to say that Gundam 00 definitely has the best animations out of the gundam series (given, it's the latest, but...) Never are certain battle scenes repeated constantly to take up time (lol gundam seed), and overall, it's amazing. I love watching it in HQ. ;D
Expect little character development, though. It exists, but it's not that noticable.