Well, anybody with a little old single-O like my 18 knows they're the opposite of "too boomy". A brash midrange though.
I played a nice 74 D-18 at the Twelfth Fret during my quick trip to Toronto last week. Priced reasonably too. (As these things go) Twould make a nice pair with the O-18 which is a 73.
Not gonna happen though.