My mom works at coke. I've tried "Sprite Green" which is the new sprite sweetened with Stevia (I'm not sure if it's available to the public or not). It has an unusual aftertaste but otherwise tastes like you expect sprite to taste.
I think I'd much rather have sugar in my soft drinks. Maybe I'm CRAZY!? But then, I do trust stevia a bit more than I trust sucralose..... which isn't much, granted. But at least it's natural.