Recently bought new shades. Things I was concerned about:
1. 100% UV Protection.
2. Colour = Amber. Since I'm a simple VFR driver in northern BC, Canada, I need something good in low contract (flat light) conditions. Grey lenses diminish contrast in these conditions by 'hiding' the grey shadows. Our eyes are very responsive to yellow light, but yellow lenses are too intense on a bright day (duh)! Amber is a good compromise. I find that in low contrast conditions shadow edges are easier to detect with my shades on than without. Brown lenses are pretty good, too.
3. Photochromic. Want 'em dark on a bright day, bright on a dark day. Wanna be able to wear 'em in low light conditions to take advantage of the amber/heightened contrast effect.
4. Polarized. Lots of water up here in the summer, with lots of glare. Don't seem to have any problems reading the GPS, comm, or clock displays. These are the only LCDs on board. I have noticed the 'gas pump effect', though. Weird... No problems with the plastic bubble.
5. Glass lenses. Not as safe in an impact, but WAY more scratch resistant. Polarized plastic lenses are also very hard to find.
So there's my two cents worth. Looks like you're getting plenty of information. Great forum, eh?
Enjoy your new shades!!