I am not an alchohol drinker (not technically old enough to drink either), that being said I have never drank or smelled a martini. 
  
My first thought when I smelled Twenty One I couldn't pin point the smell until right now. . . TO ME it smells like a ginger ale. I LOVE the smell of ginger ale.  
  
I first smelled it from an imp and then tried the bottle, the same AMAZING scent and I completely love it.... off to order me a bottle...