I hate the cars movies they bore me to death, but I love carsland. The theming is excellent imo and it offers a great and fun time even if you just ride one ride there. Plus it has soft serve, and I love me my ice cream.
Also before going to carsland, I was not expecting to be bored despite the movies boring me simply because of the amount of exposure rsr got. Not to mention disney's rides are usually fun for me, even the kiddie ones (spinners and the like). The only thing that bores me at disney are the shows, but those can be easily skipped.
Basically the lesson here is don't judge before you ride, IP or otherwise. You might have a great time, you might not. But at least you and your kids can at least say that they experienced it.