I have a very mixed relationship with the "Cars" films. They were among the first films that I watched with my youngest brother and the first films that he really liked. He owned a lot of the toys and play-sets and even today, we can quote most of the films by heart.
On the other hand, it's not hard to see that these films are on the lower end of Pixar's oeuvre. The character of Mater is still fun, but never as resonant as Woody, Buzz, Mike, Sully, Wall-E, Carl Fredriksen etc. The visual gags and style is good, we're still talking about Pixar here, but it's pretty clear that this isn't their A-game.
The whole spy-plot is fun though and I enjoyed my rewatch of it in preparation for the third entry in this series, which I heard is better than the first two.