I'm actually impressed particularly by Q - the eyes/nose/mouth give a surprisingly good resemblance. Beverly is also quite realistic.

The rest are recognizable, though in a bit more of a cartoony way. Though I think if you changed Data's mouth, he'd look less cartoonish. Picard is quite good too, but I don't know if there's a taller head available.

I'd say (as constructive feedback, not criticism) that Riker is the least recognizable. As I recall, he has a surprising eye shape, and these big round ones don't evoke him to me. He also has a hairstyle that is not a typical one you find in many "character creation" libraries, and that often makes it hard to get a character that looks like him.