Actually, I've been fiddling around with it now, and have managed to get it to work a bit better (a second index rebuild seems to have done the trick, plus re-enabling "Search entire index in Start Menu"), and the thing I like most is the natural language search, because it lets me type things like "beatles folders" and get only folders that are under my Beatles directory - which I can then right-click at my leisure.
I would still like it to be smarter and let me use NLP searches for properties - "mp3 where genre is jazz", or even decipher the shorter "jazz mp3s" - but I don't know if it's there yet.