It is absolutely delightful! The Campari and mezcal harmonize really well with the standard margarita ingredients.

As others have said, it can get a bit salty if having salt in the drink as well on the rim. Maybe skip the saline and just go with the Taijin, or use a non-salty chili powder alternative. Not sure if available in UK and Europe, but Mrs Dash southwest chipotle would work!