I ordered this because our local CQB fields require full-face protection.
It does its job well, it is surprisingly very comfortable. It does cause some fogging after a while in my goggles, but that's normal and would probably happen anyway.
You can definitely still tell you are getting hit, which is a good thing. There is also a loud sound that you nor your opponents will be able to ignore, which should give some a little more incentive to be honest, hopefully.
The straps are a little awkward to work with and adjust, but once its done it doesn't move around very much.
Protects your face and teeth
DOES allow you to use virtually any sights you could use without the mask
May cause some goggle fogging
Somewhat difficult to adjust