It's just a matter of taste I suppose. Devin's signature sound that is present in all of his music is the wall-of-sound approach. All of his music is incredibly layered. And I like the genuine emotion in his music. He is bi-polar and it shines through in a lot of his projects. You can hear the mania in his voice almost. Sometimes it might sound angsty but atleast I know it's genuine, you know? I don't know how else to describe the appeal to me. He is an interesting person who makes interesting and unique music and that is why I like him.
It took me a while before I liked his stuff so maybe you should just give it a more thorough listen or something. At first it didn't seem very special to me but after I listened to Oceanmachine - Biomech for a whole day it clicked with me. That's still my favourite album too. It's a little more restrained and introspective than most of his other work.
Shrug.