We had a good lunch at Quattro Venti. Ideally located on the cathedral square the food was well prepared and quite good. My wife and I both had pasta dishes and both were excellent. The service was professional, if, in my opinion, a bit brusque.
Our lunch was marred by two things that weren't the restaurants fault: a screaming child in the square, which demonstrated how great the square's acoustics were... The child was 100 yards away, but It felt like he was right next to us... And, some tourists, having tasted a bit of wine, decided to play piggyback, falling down on the table next to us, while we were doing lunch. Welcome to the downside of outdoor lunches... Again, not the restaurants fault but definitely part of our experience.
So, the food was decidedly good, perhaps the server was having a bad day, and hopefully the piggyback folks don't return. If so, you may not just have a good lunch (which, I'm certain you will...) -- you may get a GREAT one.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.