Quoted from sepins:I assume Bob's pinball glass is worthless?
In terms of glare reduction it's barely better than a standard sheet (6 of my games have Bob's Ultimate, they do look nice but don't block backbox glare). I find that putting a strip of LEDs above the backboard on the game to light up the upper playfield and using a bent plastic helps a lot with glare for $10 until I get my act together and PDI my games out.
This video is the consensus I've seen on PDI vs. Invisiglass...