I was out of Angostura Bitters, so I used Hella Aromatic bitters instead. Worked really well. The classic Manhattan is a favorite for me, but substituting a good Anejo tequila is a brilliant twist. Loved it.
Had again, but this time using the option of all chocolate mole bitters instead. Wonderful also. Slight hint of chocolate and a bit more of an aperitif. Both are wonderful.