I was extremely skeptical when I was trying to choose which lens I should buy, especially because the Blue Mirror lens is over twice the price of some of the other choices. However, I just got done with my annual trip to Vail/Breck and these are the greatest lens you could ask for as they are usable in all conditions, blizzard or bright sunny day.
All of my friends were complaining that on sunny days their orange or persimmon lenses would be great on some runs but if we were to duck into the trees or even if it suddenly became cloudy that it was very difficult to see the terrain. However, my lenses let enough light in so that you can see in low light conditions but they are also great in sunny conditions thanks to the mirror coating.
If you can afford these lenses, they are worth every penny.