I don't know if any of them are using it in soft drinks but Xylitol is pretty safe. It's a crystalline alcohol found in most plants. It tastes very much like sugar, more so than most sweeteners. It can cause diarrhea in some people and is very toxic to dogs.
Word of experience - don't use Xylitol to make ice cream. Since it's an alcohol, it's also and antifreeze. Your ice cream will remain a liquid to WAY below freezing.
