Well......this won't be much of a classic, but......it's not bad.
They could've made a few changes here and there and leave out a scene or two, but overall. It's not bad. Course, it follows the same plotline as Tory Story 1 and 2 a bit and added in some things from Toy Story 3 in there. But, it's quite a pleaser. No, it won't be a classic by a long shot, but it's a passable movie to watch on a rainy day.
Illumination has yet to get themselves an instant classic on their hands. So far, they only have a couple hits and more misses.
Though, not sure about their new upcoming movie Sing which is another anthromorphic type of movie. Much like Zootopia. Perhaps they'll try to cash in the popularity of it, but from the trailer. It doesn't look too bad.
Overall, Pets is an ok movie. Kids will like it. Adults will laugh at some of the jokes. But, it's rentable.