If you like a Negroni, you'll like it. If you don't, you won't. Personally I think Negroni's are too bitter so I doubled the cognac and added a skosh of Licor 43 to "simulate" the flavours of Carpano Antica. Still a bit too bitter but a lot more to my style.
Very good as written but also works great Valentino-style with (2:1:1) proportions (1.5 oz cognac, 3/4 oz each vermouth and red bitter). Used Antica Formula and Martini & Rossi Riserva Speciale Bitter. Served it in DOF glasses with both orange and lemon twists. Excellent!
I just made this using your proportions and it was delicious and very balanced. We'll be using this recipe often throughout the winter holidays, I think.
If you want to step more away from that sweet, Negroni-like profile, and for an extra layer of flavor, I'd suggest splitting the red bitter liqueur to allow for that darker taste of coffee liqueur. So try 3/4 oz red bitter liqueur and 1/4 oz coffee liqueur.
This was good and added a nice subtlety to the cousin Negroni. The cognac vs the gin drew more of the fruit out of each of the sweet vermouth and the Campari. I do like it, but not sure I would run to this when after this flavour profile.