He obviously has a razor - he leaves his lip bare - so I guess he just prefers his eyebrows like that?
As a bear, Beorn is a wild, unpredictable berserker. As a man, Beorn is polite and stoic, though he does express a dislike for the greed of dwarves. He talks freely about his past and his people; he says that Azog the Defiler killed most of his family and enslaved the rest. The slaves were tortured for sport. A manacle on Beorn's wrist implies that he was once such a slave. Beorn pins the genocide of his race on Azog, and claims to be the last survivor of his people.
The Book: Beorn isn't described as having such an exotic appearance; he is "a huge man with a thick black beard and hair." He is rude, interrupting and makes demands of his guests. When in a better mood, however, he is much jollier; cracking jokes and laughing loudly. He does state that he is not overfond of dwarves, but does not mention their greed or selfishness. Beorn is seen speaking to animals in their own language. There's no indication that his personality changes as a bear or a man - however, both Beorn and Gandalf warn the dwarves not to venture out at night, while Beorn is wandering around as a bear, "at their own peril." Beorn enjoys stories; he is pleased by Gandalf's recollection of their journey thus far, and over dinner he tells tales of his own adventures in the forest. He does not mention his past or his people. Gandalf surmises that Beorn is a descendant of the "ancient bears of the mountains," or descended from the "first men who lived before Smaug," but admits that he does not know the truth. Beorn is also not the last of his kind. Very little about his people is ever stated in the books (or even if they are a separate race), but during the Council of Elron, Gloin made a mention of Beorn's son, named Grimbeorn. There's at least one other.
My Opinion: Beorn was nothing like how I imagined him. I guess he's technically not far from how the book describes him (I'd hesitate to call that thing on his face a beard, though), but I always imagined some great big lumberjack, or a Hagrid-looking dude. I think the mohawk and unique beard are just silly. Not everybody has to look special and unique. Some people just hang out in the woods and don't shave. His personality, too, was different. Beorn of the Book was a man of passions and wild moods. Beorn of the Movie was stoic and serious. Why the change? This version of Beorn is just... boring.
My girlfriend disagrees, for some unfathomable reason.
I prefer the movie's version of Beorn's history. Making him one of the lone survivors of a race of badass shapeshifters is pretty neat. The book's implication is... absurdly stupid. I'm sorry, Tolkein, but it's quite silly to say that he is either descended from ancient bears or from ancient men. All men are descended from ancient men! All bears are descended from ancient bears! If he is not under some enchantment (as both the movie and book claim), then why not make the claim that he is a member of a different species?