I personally teach kids with autism. I have also been around classrooms with kids in autism. Purposeful, intelligent socialization led by an adult who understands kids with autism will make a big difference to social skills. There are little things like eye contact that make a huge different to their life experiences. I have recommended social groups many times, and the kids have found the experience rewarding. I have also given specific pointers that have made large differences, but the social groups did a lot of the foundation laying for success.
If I had a child with autism, I would certainly send them to a social group. Of course I'd look around for the best I could find.