This film is somewhat hard to describe with words. They would never be able to transmit exactly what we feel when we see it. Maybe because this film has something grand about it, like one of those classic melodramas (but not too much wimpy), that makes it a masterpiece. A film so deeply human, so overwhelming, so heartbreakingly beautiful... and yet never condescending to its doomed characters. It's a film that will never lose its power, in part thanks to its gorgeously framed and lit scenes, and also thanks to its central perfomances - especially Cotillard and Phoenix - that give a whole new dimension to its characters. Bruno Weiss, Phoenix's character, was for me the most interesting and complex of them all, managing to be hateful yet somewhat endearing at the same time.
In conclusion, if you're interested in seeing "The Immigrant", then just do it. If you're still hesitating, take a chance and go see it. Watching this film will never be a waste of time: even if you find overly melodramatic, you'll admire its grandness and its frank deconstruction of the American dream. An instant classic that demands to be seen.