I have a Superglide and they do work as advertised.
Besides the hitch/un-hitch angle issue, which has yet to be a problem for me, but I have avoided getting into situation where I could have used it. With older hitches, I did sometimes hitch/un-hitch at as sharp as 90.
One other thing is the capture plate that you must have on your king-pin box. The biggest problem with this is that no-one can move your 5er for you. Maybe not even your dealer (if they lack an adapter). Yes you can talk the capture plate off (unless it is welded on). But bolts and nuts rust....