Zevia, an "all natural soda" is sweetened with stevia and caffeine free.
Mark Sisson has already done one heck of a breakdown on stevia. In short, stevia looks to be a better alternative to other sweeteners and it may even have a net therapeutic effect.
For diabetics and dieters who need an occasional soda fix, or miss the comfort of the carbonation, this looks to be the a good product. It uses erythritol as a medium for the stevia, which is probably pretty benign. I had two tonight, so If anything funny pops up I'll post an update.