Best analogy is white bread vs sourdough. The extra bacteria hanging around make for a more complex, but less consistent flavour. It will vary by season, by year, and by maturing environment. Raw milk cheese has terroir by the bucketload.

Interestingly (to me, anyway) raw milk can be clabbered. This is the simplest way to get a sense of the complexity raw milk cheese has (but don't do it with pasteurised milk, it's dangerous).