All I have are plastic, my safety glasses at work are too, and all of them fog up pretty easily so I wouldn't think there was a lot of advantage to plastic in that regard.
I have the shallow blue Oakley monster dogs and then 2 pair of the dark gray oakley lens, one in monster dog frame and one in twenty frames. I have enjoyed all of mine alot and all are polarized but, that said, I haven't owned Smith or CDM's so I can't say my preference to the Oakleys. They are just really comfortable to me and don't give any distortion therefore no headache or eye strain. They are also extremely tough in regard to dropping, scratching, etc. and seem worth the price to me.