Given my interests, it would be very difficult for me not to have enjoyed this film, so I may not be the most neutral judge of its merit. I would say that this is a good biopic, though also the least interesting film I've seen by director Raul Peck.
If Hollywood were to make a biopic of Marx and Engels, which it would never do, it would probably look a bit like this: good set-pieces, solid acting. There's a bit too much focus on the two men's love lives. (We need out watershed thinkers to be sexy!) As in almost any biopic of a creative person, there are some ham-fisted moments that attempt to depict major moments in the subject's creative development, including a rather laugh inducing one concerning the most famous quote from the Thesis on Feuerbach.
On that note, the way in which it seems to me that this does stray from a Hollywood treatment is its attempt to, superficially at least, explicate some of Marx's early philosophy.