Have you seen it? I really liked the movie. It didn't make me laugh continuously, but I felt it was layered...comedy on top of a good, thoughtful story with wonderful touches throughout. I found most of the characters to be sympathetic and real. I like a movie where I care about the characters. And I thought the final scenes were terrific — and very funny.
I do have one complaint, though. They have the grandfather snorting heroin. (This is not a spoiler.) I know it's an R rated movie, but a lot of young people will see it. I think it's a mistake to trivialize heroin use like that. They could easily have had the grandfather doing something else. It didn't even have to be related to drugs. The movie doesn't get into his drug use, so there's no mention of how highly addictive heroin is. It's just something funny that Grandpa does. Not a good idea, I would say.
I admit I have a strong anti-heroin bias. The drug has invaded our rural communities and is swallowing up our children. One reason heroin has been so "successful" is that kids are unaware of its wickedly addictive properties. They think it can be used as an occasional recreational drug. And that fallacy is exactly what this movie perpetrates.
When I saw the first drug scene in Little Miss Sunshine I thought Grandpa was snorting cocaine. Cocaine certainly would have fulfilled the intention of showing Grandpa to be inappropriately cool (in the extreme). Of course, to me, pot smoking would have served the same purpose. But maybe I'm unusual.