I spent 8 years of my life working at Sunglass Hut, as a multi-store manager and corporate trainer. So I know a little bit, but it's been 20 years since I considered myself an expert

Definitely look for polarized lenses which block reflective glare off of water, snow, roadways, etc.

Polycarbonate (plastic) lenses are lightweight and virtually shatter-proof, but they will scratch easier. Glass lenses are heavier but resist scratching. Any glasses with a reflective coating on the outside will show scratches more easily because the coating is the first thing to be damaged (especially when wiping dried saltwater off with something like your shirt).

We only sold a limited number of Costas back then, so I don't know a lot about them. I used to swear by Serengetis but have worn Maui Jims for the past 15-ish years. I *love* their lenses and their customer service is the best! I had some scratched-up lenses that I sent in for an estimate for replacement. They sent me a brand new pair for $35 (which if you consider the retail cost, this is a hell of a deal). I have three styles - metal frame/glass lens, plastic frame/glass lens, and plastic frame/poly wraparound style lens. I use the plastic/poly the most.

But it's ALL about personal preference (lens color, style, etc.). I'd definitely recommend going into a retail location to try them on - preferably one where you can actually walk outside with them to compare and find what's right for you. I used to let customers do that if they left me their license and a credit card.

Felix