I don't make that statement lightly. All of Pixar's movies some degree of excellent (mostly a high degree) but I really feel this one exceeds them all. It has deeper themes, and realer characters. The story itself arises from real human drama and tragedy. How they can pour so much emotion and heart into computer generated images is beyond me.
I hope Pixar can continue to top themselves... they make it harder each time, but they haven't failed to deliver yet.