San Francisco is a nice place to live if you are making a good wage, but it's been stripped of personality. The thing that made San Francisco an interesting city to live in left, years ago. For instance, middle class persons can no longer afford to live or raise a family here. If you are a teacher, nurse, social worker, restaurant manager, small cafe owner, policeman, fireman, librarian, hotel worker, truck driver, car salesperson, etc,. etc. - you cannot buy in.
Add to that the sense of snobby entitlement that has begun to sink in here. The place is filling up with upper-middle-class types who are nice enough, but there is a "sameness" about them that kills the heady diversity San Francisco was known for.
Last, comparing San Francisco or the Bay Area to Florence is ridiculous. Seriously, stop with the fawning praise. The one thing that does separate San Francisco from a lot of other cities is its physical beauty. It's a stunning place. People want to live here because of that. If you look in the SOMA district where all the techies are living and working, it's become a stultifying, boring, architectually uninteresting place. Comparisons to Florence are self serving and reflect the degree of disconnectedness and lack of historical perspective shared by the tech industry. Everything is "now". San Francisco doesn't hold a candle to Florence, even today!