As of this writing, Abbott’s bitters only directly appears in two (2) recipes in Martin’s Index: the Atom Bomb and the Peacock Gallery. The rest are merely drinks calling for aromatic bitters that you could use Abbott’s in if you like.
I don’t have an opinion about Abbott’s other than I like Darcy’s version just fine. There’s a permanent degree of uncertainty surrounding the original product. (I have sampled vintage Abbott’s, but I don’t place any particular stock in that experience.)
If you are simply looking for a functional alternative to Angostura, my recommendation would be Bitter Truth’s Bogart’s. You need to use slightly more than you would of Ango, but it works and it sidesteps the Christmas flavors.