I found some C2 at Wal-Mart tonight in the course of handing over a significant portion of my last paycheck to the Walton heirs. My general first impression is that it tastes like a slightly less syrupy version of regular Coca-Cola Classic; unlike, for example, Diet Coke,* it actually manages to evoke the flavor of regular Coke.
Since it is less syrupy than regular Coke, I’d imagine C2 probably makes a better mixer with vodka. Not having any vodka (or, for that matter, any hard liquor) on hand, such experiments will have to wait until at least Monday.
Update: Len Cleavelin also has a review of C2 that goes into more scientific detail.
* For some reason known only to the Coca-Cola gods, Diet Coke tastes nothing like Coca-Cola Classic and seems to have been more inspired by New Coke or Coke II; Diet Rite cola actually tastes much more like regular Coke, though somewhat less like Coke than C2 does.