I am curious about this too, especially with regards to the gen. I have a gen 372 but I rarely wear it, and when I do I wear it gingerly, because of the plexi. i know Panerai did this for authenticity's sake with regards to the original vintage models, but they should have given the ownders with an option of a sapphire crystal. To their credit, though, they had the foresight of including an extra plexi. Also, about the "warm glow" from the plexi, it is all BS, I put my 372 beside a 422 (which I believe has the same case, but a sapphire crystal) and I could not tell the difference between the two crystals.