Gents, 
I am in the market for a new pair of sunglasses.  I currently have a pair of Oakley Industrial M Frames, my second pair in 4 years.  I am pretty rough on sunglasses as I wear them whenever I am outside.  I hunt, hike, work, or scout in them for the most part, not a whole lot of fishing but I do canoe every so often. I like the way the oakleys fit, but it seems the lenses are scratching awfully easy and the clarity with these lenses is lacking.  I have never owned any Costa Del Mars so I am soliciting input as to quality and wether or not I should stay with oakleys or try out the costas which are geared more towards polarization and being able to see stuff in the water easier.  
Thanks
Whackm