Yeah, I just wonder what third city most US tourists aspire to see after P and R. London is "OK", I've been 4-5 times. It has some "things" of interest to me, $$$ of course.
I've not been to Vienna, it's on our list. My wife wants to go (back) to Florence.
My wife alternate each year between Paris and London for the major air show she had to attend for work.