I just picked up a Hobbit LE with Invisiglass and it's excellent. First time I've seen it. My other pins are normal glass and have way more reflections! I know a guy who has Stern HD, Voodoo, Invisiglass and PDI. He said Voodoo is the way to go for the price. But PDI has nice polished edges...who cares? You don't see it when installed.

PDI is the best, but I'll stick to Voodoo. Good enough and a lot cheaper and more available.

OK.
I don't know. I never compared PDI to anything. It's just what several people who claim to have all four types have said. Stern-HD, JJ-Invisiglass, Voodoo Glass, and PDI/Roman Glass. I'm happy with my Invisi and Voodoo.