I'm an optometrist, that's where I get my chatname. I usually just tell my friends who ask to go find a good pair of Maui Jim or similar polarized glasses at Costco (I work there sometimes btw). That's assuming they want something polarized and can find something that fits well and looks okay. Btw, most fashion conscious (women) will not care much about sunglass lens quality, they are just looking at style.
I've never had a pair of Costa del Mars or Harkens, but I've had tons of high end sunglasses and even some cheapos. I'd guess my favorite pair ever were a pair of Serengeti Stratas which were polarized and photochromic, the only pair with both those features that I've ever had. Mine strangely sort of peeled apart a few years ago, maybe that's why they were discountinued. Serengeti is a branch of Corning so they use glass lenses. Most of my Maui Jims have used glass lenses also. I like glass lenses in a car but I usually find myself picking up some of my lighter sunglasses when boating. My current favorite boating sunglasses are an ugly set of polarized Bolle's with a side shield type design.
I have quit wearing polarized sunglasses much in my BMW. It's radio display is polarized, plus I have tinted windows. I do have a radio display "fix" that I slip in at times. What I did is bought some overhead tranparency film at Office Depot. Tranparency film is also polarized so you can tilt it to shift the display polarization. This fix can be used for boat displays etc if you otherwise prefer polarized sunglasses. Beware though, the display will be visible but not perfect and the film itself will cause glare when your not using sunglasses.