I liked it! 5.7 is too low.(spoilers)
This movie elicited more than several 'laugh to tears' moments, and I'm actually perplexed it didn't do better in the ratings. The only criticisms I have are that it should have been shot in colder parts of the US, or at least have their relatives live in colder states where there's snow for a more Christmas feel, and the part where they temporarily split up pushed it into 'bummer' mode a bit.
BUT, all in all, I think it deserves a solid 6.5 to 6.7, although several parts of the film lift it to a 7 in hilarity!.