Most of the time they are interchangeable.
If used when expressing an opinion then i’d say that you can use either.
I don’t like the cold, how about you? / what about you?
However, what about you could also be used like this...
What about you do you dislike? Or What about you do people first notice?
These are not the best grammar but nobody unless an academic would question them.
I hope that this helps :)