This serie is amazing!
I'm working with autistic people and I can tell you that it is spot on! (from the autistic behaviours to the special schools and carers)
Though, this is not a serie about an autistic kid (like atypical which is about a teenager boy), but it's more about how a family struggles, succeeds, fails, and evolve with a child who is different.
The acting is really good, from the kids to the grow-ups (especially Christopher Eccleston).
The choice of the songs are also great!
I was expecting a fourth season, but I can see on IMDB that it's not going to happen...