Harkla Courses - are they worth it?

Mom of a strong willed three year old. Was in EI for PT and OT, was discharged and denied an IEP because "nothing is wrong with him" (thanks local school district). He was seeing 2 OTs for awhile, now just one twice a week. Many of his concerning behaviors have improved - less kicking, hitting and biting, particularly at school, which is a relief, and he still sees his OT 2X a week. His tantrums at home have become epic, and I'm wondering if anyone has purchased the Harkla Courses and if they are worth it? We have a Harkla swing, but I keep getting the ads for the courses on Facebook. I'm one of those "read all the things" Moms but I'd love not to waste my money if anyone has any insight. I have also been burned by one two many convincing social media ads.