I could immediately see why Autistic people took issue with Sheldon's portrayal. While an accurate depiction of some Autistic people, all of Sheldon's Autistic behaviors were mocked and/or laughed at by his friends, or by the studio audience. Rarely, if ever, (at least in the episodes I saw) was Sheldon treated in as an equal by his friends. He's manipulated into doing what the others want, reprimanded for not recognizing social cues, and the list goes on.
Definitely not a show I'd recommend, as far as disability representation, because disability is not the butt of able-bodied people's jokes. We are not lesser than. We do not exist to be mocked or manipulated.