Sorry for not responding earlier. I have basically been away for most of August in the USA.
I have 4 sheets of JJ glass and about 6 PDI. I have swapped them out on a number of pins. The JJ glass collects lint like crazy. Worst thing you can do is use a micro fibre cloth to clean one! It is a pain in the ass to get clean again. The JJ glass also scratches very easy. I have a few scratches from moving them around from pin to pin. If you have anything on your cloth, it will scratch the glass! None of my PDI glass have been scratched.
PDI glass is the winner! More clear, as I find there is still a bit of a haze on the JJ glass. The film is also on top of the JJ glass as Brock mentioned. You can also see from any angle on the PDI and not on the JJ as it gets a bit hazy on when standing to the side.
Overall, I would definitely recommend this glass for all of your better games. If you can afford to, I would put it on all of the pins. If you only have 1 or 2 pins then it would be a must. If you want to step it up a notch, I would add the glare guards to your DMD. I haven't as I don't like the look of them on the pin cosmetically but it would make the glass perfect!
Shaun