I think one should make it with a pretty good tequila, as it's a spirit forward drink.

As a spirit-forward drink, the nature of the bourbon has a big influence on the final taste. Made it with Jim Beam Bourbon, didn't find it so great, definitely would like to try it with a finest bourbon.

Maybe the best stirred cocktail I prepared so far. Gave it a 4/5.

Very enjoyable, easy to drink. After reading the comments, I tried it two times, both without sugar syrup, and increasing to 1/2 oz the grenadine syrup. I found it better with only light rum (the first time I put a little bit of Smith and Cross). I still found it quite sweet, maybe I would try next time with the right amount of grenadine and sugar syrup (and another time without sugar sirup? And maybe another time...).