I've boxed for three years and i'm quite an expert on boxing (i was also writing articles on usa boxe for an italian site years ago). Well, boxing is surely good on a street fight, but it also depend on the boxer, and his category, if you're a fit heavyweight it's obviously easier. It also depends on your natural punching power, there was a guy at my gym who knocked on the floor 3 albanian guys who fuck with him on the streets, but guy guy had natural punching power. Also a guy from my gym once knocked down with one right hand a very big security guy at a night club, he was 80 kg but he also get 3rd at the italian amateur championship. So it depends even on you and your natural power, but that also depends on how many years you trained etc.