Stevia is a natural herb that is used for sweetning. Recently there has been some debeate on it being an insulin trigger.

Erythritol is a new sugar alcohol with almost no calories and the lowest GI of any other sugar alcohol. I cook with it occasionaly. It doesn't always disolve leaving somethings kind of grainy. It also isn't as sweet as sugar so you often have to use a small amount of other sweetner such as splenda or stevia to get a sweet taste. I think it has a funny taste, but that oculd be I'm just not used to sweet things anymore.

The #1 down size to erythritol is I've only found it in small amounts and expencive.