Admittedly, I'm a fan of stevia and use it (or products with it) at least 3 or 4 times a week. But for those PWMEs with low blood pressure and/or POTS/OI issues, you may want to avoid stevia or, at least, use it sparingly. Stevia lowers blood pressure, and this can be a problem for people who already have low blood pressure.  
Stevia, it turns out, also helps lower blood sugar and is sometimes used as a treatment for those with hyperglycemia. Since my blood sugar tends to run a little high even after switching to a low carb diet, I will continue to use stevia in moderation. Incidentally, my blood pressure normalized after the first 6 months of having ME/CFS, so I'm more concerned about blood sugar than blood pressure, but I realize many of us have the opposite concern.