It is definitively a slow, but pretty intense film. Most of the tension for me came from the fact that I the closeness of the community he lives in became tangible. Interesting is, that this lower middle class family already starts from a quite unrealistic outset: Money is short, but they struggle - and they manage... somehow. Obviously, the main character's illness pushes them below the waterline pretty quickly. A family like that in 2012 would already set out underwater.
The biggest surprise for me was Jessica Chastain. Finding her character at few points a bit annoying in Tree of Life, I felt she really found the perfect balance on her - imho extremely difficult - portrayal of the mother and partner. Most impressed by her work - too bad she's already such a big star. (she still DOES seems to read smaller scripts)
Another perfect moment in the story is the meeting of the husband with his brother. Between brothers - especially if there is a "past" - there is so much subtext that it just bursts at the seams. Loved it.
I would have left out the very last scene. We know what they're looking at - nothing on the screen could have surpassed what I had in my mind just then.