Is Diet Pepsi better than regular Pepsi?

That depends on if you mean tastes better or better for you. If you mean tastes better, then that would be an answer that would differ depending on who you ask. If you mean better for you, then that would also be an individual determination since some people can not have sugar, so Diet Pepsi would be better for them.

I personally like Diet Pepsi better than regular Pepsi but mostly because that is what I am used to now. However, I like Diet Pepsi best with some fresh lemon squeezed in it.