Really? I wouldn't even put it in the top 20. A modern city centre with no personality that clashes with the old surrounding areas. It doesn't even look particularly German with 80% of it rebuilt after the war.
Take a look at places like Bergen- Norway Ptuj -Slovenia, Venice?
He was clearly joking/being sarcastic.
Nah, I'm serious. But I may be just a little biased because I am from Frankfurt myself. I have been to a lot of cities, but I just like Frankfurt best. Mainly because of the hessian culture. (Is that correct? I don't know the translation for "hessisch", Goolge said hessian xP). There is even a building that looks like a glass you use for drinking apple wine. People just call it "Geripptes". I love that. We also have the best food! Franfurter Grüne Sauce is the best meal that was ever invented. Period.
I know I might be in the minority, but I still like Frankfurt a lot. =P