I actually like his voice.. It's.. different.
Lyrically, I think he's terrible. It sounds like the rest of the stuff you hear on the radio. However, his songs are really catchy. I kinda just play them unconsciously and dance around, but I never really pay attention to what he's saying.
I don't really have a strong opinion about his mixtapes vs. his album. I've listened to all of them but I feel like they're almost the same..