^^^ Truth. I had one recently with mezcal in place of gin and serrano. The smokiness of the mezcal and the heat of the serrano complemented the tang of the lime/maraschino and sweetness of the Green Chartreuse perfectly. On a related note, I actually prefer the negroni's cousin, the agavoni, which substitutes silver tequila for gin. The vegetal nature of the tequila similarly complements the bitter orange of the Campari really well.