Artificial Sweeteners - How Dangerous Are They?

What is the big controversy over artificial sweeteners? Is it really that bad for you? If it is, why are over 200 million people consuming it on a regular basis? It has endless adverse health affects that people may not be aware of or maybe they just don't care. They may feel the effects but do not know what the cause is and wonder why modern medicine can't help them. I recently tried a popular brand of powdered iced tea and I noticed a nasty after taste. I believe it had an artificial sweetener containing aspartame.