You might have missed the trailers for Max. I can't tell if it was under-marketed, or just heavily targeted away from me. Given the number of "kids" movies I see, I find it odd that never saw a trailer, and only caught one commercial on TV.
Short version: A fairly typical feel good kids movie, but very well done within that genre. The plot felt mostly realistic, the characters were fairly three-dimensional, and the emotions were surprisingly complex. While it's not a movie that anyone needs to see, it's also a movie that you will likely enjoy watching.
Oh, and the important bit: The dog does NOT die. I was a bit worried when the poster said "From the producer of Marly and Me".