Haha it's the other way round for me. I think his songwriting skillz - melodies, hooks and so on are good enough, and the propulsiveness of their dancey numbers effective enough to carry him along, but when the arrangements are sparser his vocal failings are magnified a lot more. (A pity because I think some of their ballads would be really, really good with a better singer, or someone who wasn't so QUAVERY at least.)