I use it quite often. It comes in several different forms. Powder, tablet, and liquid.
Stevia is an herb and has no known side effects.
I don't care for it in hot liquids such as tea or coffee, but love it in my iced tea, Kool-aid ect. But I mainly use the powdered form and have been told that the liquid form of stevia is much better for hot liquids.
I don't have a brand - I buy it in pure form in the bulk section of my health food market. But there are numerous brands out there. Some brands add fillers to the stevia so I'd watch out for that.
As far as taste, if you get to much it has a slight bitter after taste. A little bit goes a long way. But for the most part I don't think you'd notice the taste.