I used to use this in my coffee just about daily, and then I went off it for a while after my supply ran out. I picked up another box of the little packets the other day, and it seems so much more bitter and overpowering to me now. I don't know what the deal is.
I do know that my girlfriend put together a taste-test project for a statistics class, and out of cheesecake made with aspartame, sucralose, and stevia, I'll be damned if the stevia cheesecake didn't taste the best.