Do your research, weigh the pros and cons. In my case, the ultimate criteria is
go by feel - the body will not lie.
For example, even though Aspartame is a highly controversial topic, I found by trial / withdrawal / unexplainable mood swings that I was highly sensitive to it. I used to think the caffeine in Diet Pepsi was the thing that gave me the
kick I needed to go through the afternoon. Boy was I surprised to learn that aspartame is classified as an excitotoxin.
Stevia - cool if you can digest it. I know I can`t, and the gas produced by gram of that stuff in my case is almost painful.
Sweeteners are cool, but eventually you can do without them. Most people would think my crushed flax powder (great protein supplement, no gluten, tons of fiber) tastes bad. I got over it rather quickly. Your mileage may differ.
So, in the end, do your homework and go by feel.