Tonight, I mixed two Negronis using Plymouth gin and (of course) Campari - but with different vermouths. The first used up the last of my Carpano Antica Formula, and the second used Vya red. Both were mixed at the classic 1:1:1 ratio, stirred over ice, strained, and served up in a cocktail glass, and no extras were added - sometimes I like to add some Fee's or Angostura.
The difference was remarkable - yet I'd be hard-pressed to pick a favorite, as they were both fantastic. The Vya version showed the characteristic Vya cinnamon/clove notes, and was a bit sweeter, while the Carpano version was more herbal, with a bit of a bitter edge beyond the Campari.
The bottom line: Carpano and Vya are expensive, but worth every penny. I've always felt that better ingredients make better cocktails, in any case!
A couple of weeks ago, I tried varying the gin while using Carpano. Hendrick's Gin is quite a bit more delicate, and worked best at 2 parts gin, one vermouth, one Campari. If I use the standard version of Tanqueray instead of Plymouth, I can tell - the Tanqueray is a bit bolder. Any of the three make a refreshing drink.