I had worked with autistic children for a few years and definitely music was always a positive experience.

I even started a little music program where we sang songs used a computer to write & play music, and one child even composed his own tunes, (he was high functioning and could play the piano quite well) They were quite good compositions too although he never wanted to save them (which I respected). Other children had a talent for music and one boy (who was blind) was a beautiful singer, sometimes you'd get a shiver down your back when he sang it was so good. (being precocious in some areas is not uncommon for autism)

But each child was completely different and each functioned at his own level, and you can always interact with them at their own level. Some have a talent for music and others dont but pretty much all of them enjoy it.

petr