John (Harrier) Farley did a great article on AoA in Flyer a wee while back. The impression that I got is that it takes information from all the performance instruments in the panel to give you the information to make a decision on AoA which can more easily be provided by an A0A indicator.
However, is it that critical a requirement? It's down to personal taste so QDM, we're all waiting to see what hoops the CAA made you jump through to fit it
Bet you wish you had a big engined J3/L4 on a PFA Permit now