So many of the studies (http://www.aitinstitute.org/ait_clinical_studies.htm) seem to have small sample sizes or other issues (e.g. some have no control group). I'd love to see a large, well designed study to convincingly show the scientific validity or lack thereof of AIT, at least for people on the Autism Spectrum.
Draw your own conclusions from the studies that exist and the reviews. Based on those, to me, it doesn't sound promising.
Edit: typo, small content changes