I enjoyed Season Six: there’s a lot more sci-fi horror and a lot less camp under Moffat’s reign, and Matt Davis is an extremely convincing Doctor (I think he’s better than Tennant). It helps that Amy Pond is blazingly attractive too.
However I’m not feeling much love for River Song, and the finale seemed pretty contrived. There are a lot of loose plot threads, and too much was dedicated to a pointless alternative timeline, with too much left unexplained (why a spacesuit, for instance).
Nevertheless it is very clever, with the overarching plot appearing throughout the episodes (rather than springing up right at the end, well lots of stuff still springs up at the end), and some hard things are asked of the Doctor.