I believe that they were introduced at the 2016 CES in early January, but don't think they were on sale until later. Did anyone here buy one in April or May? I just found the Poll option.
I bought mine in June. Truthfully, I had my heart set on the Typhoon H but after hearing such good things about the Autel and seeing the price difference, it didn't take much to change my mind. They did hit the scene pretty large at CES, getting a lot of coverage from the YouTube experts who were covering the event. I think I first heard about them from FPVGuy. I know they had an earlier model that was around for a year or so before the XStar (was called something else, and was not a success) but the XStar and XSP are the products making them name in the industry.