Ok, so I did it. Bought my 2nd pair of MJ's.
The first pair were the Twin Falls, in the HT. The lenses are "MauiPure", which is their term for an advanced Trivex like plastic. That pair is VERY comfortable, good in low light, and probably my favorite all around glasses. So light you don't know they're on. But the polarization, while very good compared to mid-tier brands, was a step below my costa's. The reason is a touch of birefringence (which is common in any plastic, including Costa and Smith and others).
The costa's are fathoms with 580 glass green mirror and superb polarization, but they are a little dark for my tastes. Great for coastal areas I'm sure but dark for 90% of my forested PA trout excursions. And Costa doesn't have anything really between about 12% VLT and their plastic "sunrise" lens at 30%. And since I have a dark and a light pair, I wanted a "medium" pair, and I wanted them to be glass.
The new pair are MJ "Peahi" model. Glass, with their bronze lens. An old MJ site showed them at 16% VLT, but they took that down and now don't post VLT unfortunately. Still, they fit the bill.
And holy moly. I mean, wow. And this from a guy with plenty of high end shades, including some from the same brand. The polarization tested out just slightly superior to the costa's. Like the costa's, there's no birefringence (that's because both are glass), but the computer screen test proves they block out a slightly wider range of angles. Haven't tested them on the water yet. To be clear, in terms of polarization, it's close, MJ wins but only by a nose.
But the part that blew me away is the clarity. Once you have them on, they almost don't seem tinted at all, the colors seem more saturated but still natural, and crazy sharp. The Costa's cast a STRONG amber/copper shade, but these do not. Tested side by side against the costa's, there's no comparison, distance vision seems sharper with the MJ's.
My one remaining fear is that once I start hiking around in them they'll fog up. This model fits tight to my face, not a lot of air flow. I can trade them in for 90 days, so I gotta test that out...
Having played with Smith, Costa, and MJ, my experience is this. Glass beats any plastic. Always. Regardless of brand. Not only is it sharper, but for a fisherman, birefringence harms polarization, and glass lacks it. I would assume this holds for Ray Ban and others that make glass an option as well. But if you are comparing equivalent materials, all 3 have excellent polarization but MJ is clearer and sharper.