I had read the book about two years ago. Even then, the part of the story which had hit home was not the bit about the young Phd student and his wife in a strange land, but the bit about the son and what he feels about the father.
About the movie - I think it was very well made. Though I am not Bengali, the characters seemed very real to me. I also do not remember the book very well, but I think that the movie did an ok job in giving it life. The story reminded me of a simpler time, back in India and also here. It reminded of me as a person who had just come here - quite a fool I was then (No claims to the contrary for now!).
I wish I could write a better review which would do justice to how good I think the movie is, but some of the things I felt are intensely personal and I would rather let you find your own joys and sorrows while watching this one.
On an unrelated issue, the rank is #8 now, on google.com. I think that regular posts should help take this up a bit more. I would like to make a point about quality of rankings there as well - rank#1 is a dead link and has been a dead link for the past 6 months. WTF is going on!?!?!