What do you mean by "good"? Do you mean healthy, do you mean it tastes good, do you mean for diabetics, etc? I can't answer your poll without knowing what you are talking about.
In general, Stevia is a sugar substitute. I find it tastes OK, but like every other sugar substitute I've tried, it does have an aftertaste. If one needs to watch their calories or sugar content, then yes its good for that. It's a very good option for people who have an intolerance/allergy to NutraSweet/Splenda. Like any sugar substitute, it should be used in moderate amounts, and there many be individual reasons why a person shouldn't take it.