I think 'House of Balloons' is fantastic and one of the best R&B albums of recent years. His other mixtapes aren't quite as strong in my opinion, but I still enjoy both of them - 'Echoes of Silence' in particular has some great stuff on it.
However, 'Kiss Land' is one of the biggest disappointments of 2013 for me. I don't like the production and the songs just aren't up to scratch, which is particularly problematic when many of them are stretched out over 6-7 minutes. He seems to have lost the edginess and his way with a melody that made the mixtapes so appealing. I do quite like the song 'Kiss Land' itself though.