Well here's my take on the Maui Jim Shaka versus it's closest Oakley counterpart, the matte black/black polarized Unknown: (this is glass versus polycarbonate, but read on..)
Take nothing away from the Maui Jim, it is clear, clearer than I expected. I'm not so sure about polarized plus though. I can see the polarization, but it doesn't seem as strong as Oakley's black iridium polarized lenses. One such indicator is looking at a cell phone or ipod screen: No rainbow effect with the Maui's. You're supposed to see that with polarized lenses. There is polarization there, I can see the tinting on our car's back windshield.. I'm just not convinced. I think there's a bigger reason why I can't get convinced either, which leads to the second point...
The Maui Jim black lenses let in a LOT of light when compared to Oakley's black iridium. They let in so much light that in a parking lot full of cars, where polarized lenses are really supposed to make an easy job of the sun's reflection, I couldn't stop squinting. If I'm wearing black lenses, it's not because I want to be having to squint. The polarization on the Maui's may have been really good, but on water and on the road, it's just letting in too much sun for it to matter.
And now on to build quality. No Oakleys I've ever had creaked or squeaked or cracked. With the Maui Jims they sound like they're about to fall apart whenever I put them on and take them off. The Mauis did have spring hinges, and nose grips built into the bridge, which was a nice touch, but the reality is they slid down my nose anyway. Some Oakleys do and don't do that, depending on material and how they fit you. The Mauis fit very nicely, but still slid down my nose. Nice idea though, with the hidden nose grips.
Coverage on Mauis was excellent, as is the coverage on the Unknowns. Oakley's plastic lens is at least as good as the Maui glass, and more useful in that it blocks more light.
So umm, yeah, it looks like I'll be gifting the Mauis out to mom or dad. I can say I tried them out, but they're not really useful for me. If you can wear lenses that dark and not care about that much light still getting in, then sure, why not? It's a clear lens as long as you don't have to squint.
As for the squeaking and creaking, that's what bothers me the most in such an expensive set of shades. The optics were good, although defeated by their own philosophy about light transmission. The built quality though should better match the lens quality.