I remember arguing tooth and nail with a server I worked with seven years ago about whether bitters belonged in a Manhattan. The answer is now better publicized, but I had to grab a stack of cocktail books and prove it then. For the initiate—yes, a Manhattan has bitters. However, the question is no longer whether bitters belong in a Manhattan but what bitters belong in a Manhattan. Several brands have appeared in the last five years, and producers who have been around are adding new flavors.
The maker of that crusty bottle of Angostura that was once the sole legacy of bitters has added Angostura Orange. If you're unhappy with Angostura bitters because they don't actually contain angostura bark—read the label, it's true—then you can choose Fee Brothers Old Fashion Aromatic Bitters. Want something with more bite? Add Xocolatl Mole Bitters from The Bitter Truth.
Here are some of the more available lines of bitters, with corresponding notes:
Being the most common bottle of bitters behind the bar happens to be a good thing in the case of Angostura. While it lacks the bright spice of other aromatic bitters, it's a workhorse. Sometimes you want to add just enough bitter and aromatic quality—in the case of Angostura, earthy gentian and warm cinnamon notes—without overwhelming the other ingredients. Angostura also produces a nice, spicy, fresh, orange-forward orange bitter.