I have the PetMate (I think). They do drink from it sometimes but I
have to make sure to change it fairly often since it's easy to just
figure that it is "fresh" because it's flowing.

It did take a few days before they would even look at it. Cats don't
seem to like things that are new. Once in a while I splash the water
and they get a bit interested.

I think it would work better if it were shaped like a toilet bowl.
That seems to attract them.