I'm not big on diet colas, but fruit flavored diet soda is ok, like diet orange and diet sprite type things.
Diet sodas have a nasty chemical sort of taste to me. Also, not really sure what's in them, and don't think it's necessarily what I want in my body. Kind of moot since I don't like them anyway.
I don't drink regular sodas much anymore either, maybe one ginger ale a week.