This movie could probably have been a successful production, if it was realized in a different way, but the emphasis in which nearly all characters are over-stating themselves throughout its length makes it somewhat slow and uninteresting.
As it often happens with adaptation of literary works for the silver screen, the style of this movie is rather different from that of the novel from which is taken, but the atmosphere of the working-class neighborhood in the Florence of mid-1920s is quite well rendered.
The cast too is full of very good players, both famous or soon-to-be famous, like Mastroianni, Ferrero, Lualdi and Greco, and remarkable features by some lesser known but noteworthy presences such as Giuliano Montaldo (which later will acquire his own fame as movie director), and Wanda Capodaglio, unrivaled queen of the Italian stage for nearly 50 years, who plays the unnamed "Lady Loanshark".
Adolfo Consolini, a famous Italian athlete, twice world record holder and 1948 Olympic champion of discus throw, very appropriately lends his well-built body to the character of Maciste.
The only action sequence of this movie, with Ugo and Maciste trying to reach the houses of some anti-fascists and warn them before the violent mob gets there first, is very nailing and well made. Too bad the rest of the movie is not as entertaining as it could have been.
If you are interested in the history of Italian movies and contemporary literature, try watching this one, but only after reading the novel.