I think the consensus is that no, he doesn't really. He'll plow through a Vape really quickly but he's not bulky enough to last many battles. Basically, there's no role for him where he isn't bettered by several other 'mons.
He's fun to use though. I invested a lot of dust in my SC/ShB Gengar and the only reason I'm not regretting it is that he's cool :-)