With the new 'X' series, there's been loads of grumping about the plastic lens (or window).
Since these were likely designed for LEO/professional use, the choice to skip over glass was probably that these lights are subject more to drops and impact more than rubbing/scratching of the lens. And glass cracks much easier than the plastic.
Yups it's cheaper, and not as transparent as glass, but if Surefire can reduce warranty issues with less cracked bezels, it might have been a wiser choice on their part as a business.
Personally, from having the G2's and 6Ps, C2's, I prefer the glass myself. One of my G2's has been scratched quite a bit but it doesn't really show in use. I believe my G2 was scratched up from loads of pocket duty in a gravel filled/dirty pocket much of the time on the winter, and not scratched from impacts.
The Z2X is a nice looking light, but I'm more interested in it's nitrolon counterpart, for use in the cold when winter hits.
I wonder if Surefire has abandoned the 4 flats grip of the C-series? I really like the C2's grip, and was hoping there'd be a C2X. Oh well.