Yeah it may not be for adults, and some adults may find it stupid, but if you don't think about it it's really not that bad.
The story has Alvin and his gang, going across the world, in search of jewels for a bad person, and the misadventures that they come in contact with.
So the animation is good, and the story is cute, and the songs are forgettable but it's a good movie.
I give it a 6 out of 10 or *** out of 4 stars.