In Italy, there's a wide variety of herbal, often quite bitter, digestif liqueurs known collectively as amari. I'm a big fan.
It seems that each region or city has its own amaro: there is amaro Averna (Sicily), Ramazzotti (Milan), Nardini, Meletti, Lucano, Nonino, Braulio (aged to smooth), Montenegro (Bologna - vanilla flavor), etc. As with aperitifs in France, reginal biases are often quite pronounced. The combinations of herbs and additives are, of course, usually secret and often mind-bogglingly complex. Dominant tones run the gamut from mint, to vanilla, to savory flavors such as cumin. Sweetness varies but is generally prominent. Though Campari and Fernet Branca don't market themselves as amari, I don't really see the difference - beyond the fact that Campari is often served as an aperitif instead of a digestif. It's probably a branding decision, in the same way that Punt e Mes and Dubbonet are not called vermouth, though they are.
The combination of bitterness and viscous sweetness doesn't do much for most Americans. A splash of club soda and some fruit usually makes them more appealing but then they've gone from being a digestif to being a long drink, an appropriate cooler for a balmy summer evening.
In NYC, it's fairly common for Italian restaurants and cafes to have a few amari on the menu. It's much less common in Chicago. However, I have noticed that the newish wine bar on Division, Enoteca Roma, has several on the menu and plans to add more. They're available either by the glass or as a flight of 3 for $8. I've never been to the place so I can't vouch for the quality of their food or their ambiance. However, based on their affiliation with Letizia's Bakery, I expect a ramshackle charm rather than sophistication. That said, I give them a nod of appreciation for including this relatively unrecognized category of spirits on their wine list. If you like Campari, Fernet Branca, etc., you should give them a whirl. There's got to be one that will suit your tastes.
rien
Enoteca Roma
2146 West Division
773-342-1011