A.O. knives are gimmicky at best. I'm continually disappointed to see more and more offered by manufacturers. They are a way around most of the laws prohibiting switchblades (autos), and for only that reason, I think they're alright, but the laws appear to be catching up with them, as we've just seen in Texas.
As far as function, A.O. knives are lacking. As previous posters have stated, they're cumbersome and require more work (disengage safety, check path of blade, don't follow through with thumb or finger) to open than a simple, non-assisted, one-hand opener. I've never liked autos and I like dislike A.O. knives even more. When it comes to pure knife opening function, reliability, and speed, the Spyderco hole, a flipper, and/or an Emerson wave feature cannot be beat!
I don't hate 'em, but I sure don't like 'em!
Regards,
3G