I have not put this one to the test for my self, but from a sales person friend.
Barnes and nobles and other book store chains have nice bathrooms.
I have also found the local B&N bathrooms to be respectible.
Weirdly enough, the local Walmart is also pretty squeeky clean.
Skid, some places really do better then others.
Oh sure, occasionally, even the most swanky of public bathrooms gets hit by a disgusting person, but, as far as a standard averages go, some toliets really are better then others.
... As are some check out lanes...