Critically Interpreter of Maladies was received better, but I actually prefer the novel. I read it a few months ago and it keeps coming to mind. To me that's a sign of a good book.
I really enjoyed Interpreter of Maladies, but some of the stories are better than others. I want to reread it, actually--it's been a while. I haven't read The Namesake--I need to put that on my to read list.
I enjoyed the namesake, but for me it was one of those novels where the parts are greater than the whole.