I actually started drinking Diet Coke years ago because of the aspartame. I had one too many cans of Coca-Cola that just tasted awful (this was in the Coke Classic era after the New Coke fiasco), and found that the aspartame in Diet Coke not only tasted better, but consistently better.
I think one of the reasons that regular Coca-Cola tasted bad may have been because I don't care much for drinking them really cold, and the HFCS was probably tasting bad when it wasn't chilled. Aspartame has its own problems (it's not shelf stable at neutral pH, but perfect at soda-water acidity), and to me it has a bitter "before-taste" (in contrast to saccharine's bitter after-taste) giving it a bite that I actually sort of like.
And I really do not like saccharine. I'm old enough to remember Diet Pepsi from the '80s. It was absolutely awful. And really, all this got started when cyclamates got a bad reputation. It's actually still banned in the US, due to a lack of motivation to remove the ban.