I think what many are missing is the fact that on almost any mitre gauge with an extension attached to it as long as the one on the Osborne angle set is prone to give, slip or bend slightly. The Osborne because of the third leg of the triangle forms a rock solid support.
On a typical mitre gauge it is locked into position by tightening a clamping wing nut that is fairly close to the piviot. The length of the mitre fence itself becomes a lever working on a short pivot point.
On the Osborne the lock is way out at the end of the miter fence so the lever in effect is very short working on a very long piviot.
Mechanically the Osborne should be the strongest and best able to keep an adjustment. I think it is and does that is why I like it.
I never really used one but just playing around with one on a Dewalt I noticed it was rock solid, did not give or bend, could not be forced to slip. Mindful I was playing with a demo so I wasn't being careful (it wasn't mind

). I also was impressed with how easy it was to set an angle. Yes the SS mitre gauge is simple but this was easier.