Bought these from this site while I was in Iraq in '07. One pair got stolen and I bought them again! Never want another pair of shades. Definitelu worth the investment.
Pros: Pop in a new set of lenses based on your mission or if they are just all scracthed up.
Cons: Different lenses make glasses tighter or looser. Pricey but worth it.
This review was written in the old system and had content requirements that are different than reviews written today.