I went to see this with my wife today.
We both really enjoyed it. Heartwarming, fun, a few moments of sadness, and educational...all while being entertaining. The animation wasn’t groundbreaking but it was serviceable, as was the voice acting. What I really liked was that they didn’t really try to anthropomorphise Sgt Stubby. He was clearly just a dog.
I think kids kids would really enjoy it, and history buffs would probably get a kick out of it too.