I'm going to buy my second pair right now = ).
Personally, I have no issues with fogging up. I always ride with a facemask and pull them right up under my goggles and still have no issues. If you ride a facemask that isn't right up against your face it's not a problem; for ones that are right up against your mouth (usually hard to breathe?) you may fog up some. Sometimes I go in the lodge w/ my goggles on and they fog right up... once I start riding they unfog themselves right away. Don't know how but they always do!
The mirror lenses may look cool but are garbage unless it's a really sunny day. The lenses are easy to change out and replacement lenses are the most affordable i've found - around $10-$20. I have a bronze mirror, clear lense because I used to do a lot of night riding, rose lens, and persimmon lens. I used to switch out lenses all the time but I've found that the rose is good for everything and isn't an obvious tint. I can see the snow and edges much better than other lenses or just naked eye.
The field of view is pretty great! I can still see the edges of the frame but there are times where I panic because I can't find my goggles only to realize that they are over my eyes haha.
I have almost 100 days of riding over 3 and a half seasons on mine and they are just now showing signs of wear. I still think they'll last at least another 50 riding days though.