Just received my Stern HD glass for my Stargate from Pinball Life. Overall very happy with it. As noted in other posts, it doesn't eliminate the glare 100%, but is certainly much improved.
Since I added an LED ropelight the glare has been significant. I use a homemade bent plastic DMD glare guard on all my games, sorry it was still on in the "before" pic.
With the HD glass the reflection of the ropelight is still there, but reduced to the point that you can focus on the playfield and not even notice the glare.
Now I just have to move the HD glass to my other games before I play a game!
Second pic shows normal glass on top of HD glass with reflection from light comparison.