Avdi is original tool, costs £25k plus for all options and then a monthly subscription.
Vvdi is made by xhorse, they were/are an original clone making Chinese company, as an original cloned the products were good. The vvdi range is there own and has good support, works well.
Fvdi there are many versions fly made the original and it’s a copy of the avdi, this was then copied by other Chinese companies and quality disappeared. I have all of the above, the fly works ok most of the time, if it fails it’s normally voltage related and a stabiliser works
As a pass through its excellent and has its own loader for ford, Honda, Toyota, Mazda
Svdi can’t help
All do about the same, avdi generally has latest updates then copied by the others
Thanks to JustJames from mhhauto.com for his objective review.
www.obd2shop.co.uk (Good source of VVDI mb, VVDI2, VVDI Pro, Fly FVDI)