Campari, for those of you who don't know, is a form of bitters. But not just any form of bitters - it is the bitters. In fact, I find it almost improper to classify Campari in the same category as Angostura and Paychaud's. Campari is to those two what a sawed-off shotgun is to a pea shooter.
Yes, this is indeed the mother of all bitters... but it is extremely bitter. A dash of this stuff in your boomerang will completely overpower the other flavoring agents. Trust me. You wouldn't like it.
I'm going to put this one down as a hit; but it is a hit with qualifications: Campari is an acquired taste. The first time I tried it, some years ago, I found it quite strong, but nice. Mrs. Wit, on the other hand, found it absolutely disgusting. She even went so far as to describe it as tasting like "tobacco juice" (not that she has any experience with chaw). After a few years, she tried it again last night & was surprised to find she liked it .
Yes, it's an acquired taste, but once developed it yeilds great rewards.