just my 2 cents...
I have watched the show. They mostly get it right. the little boy, Max, has Asperger's. His is not severe. It's not mild. The program has been touted as having a realistic portrayal by psychiatric professionals, parents of autistic spectrum individuals and by the other asperger's individuals I know. (I have no frame of reference as I was not diagnosed until adulthood.)
The executive producer, Jason Katims, has an Asperger's son. Teachers at the Nexus school, said said many elements of the show rang true. Some parents of children with Asperger's say they are thrilled just to have the subject treated in a compassionate way, which they hope will lead to greater understanding.
That being said, I am annoyed by any "very special episode" Promo... but i do not think that the parents were over acting in any way. I have seen the same expression on faces when I have to explain "What is wrong" with me.
All in all... meh.