Full Auto Head owners, please share your experiences

I'm servicing a 72' Commando for a friend and noticed that it is equipped with a Full Auto Technologies head. My friend only told me he has receipts from work done by CNW but I have not seen said receipts. I think he bought the bike only because he wanted a Norton and it was offered at a vert good price. It does need a bit of TLC, which I am giving it now. I would like to hear from Full Auto owners what exactly makes these heads worthy of the investment. I have no experience with them and this is the first one I have seen...