I cant comment how children will like it. probably, but they like eating dirt; so that doesnt mean anything.
the first cars is one of my all time favorite movies. we used to have it playing on loop at one of my old jobs so i have seen it at least 50 times, and still could enjoy it if i watched it again.
that being said, i enjoyed cars 2. it was not as good as the first one. as said before it was not as fun and carefree as the first. basically if you liked the first one, you will probably like the second one. but i dont see myself running out and purchasing it when it comes out on dvd