I ordered 3 pairs: black, polarized, 55mm; tortoise, non-polarized, 52mm; tortoise, non-polarized, 55mm, so I was able to compare the sizes, colors and polarized feature of these glasses. Here we go.
1. Authenticity: All of the 3 pairs were sold by Amazon.com, and they all seemed genuine to me. Not even a doubt. Solid and clear. I did notice that the black pair was missing the engraved "RB" on the back of the left lenses. I don't know why.
2. Polarized: The polarized feature doesn't bother me at all in reading LCD screens, nor does it improve the view much (it cuts out a little more light, but not much difference).
3. Sizing: I am a small guy and have narrow face. The 52mm is definitely for children: a bit tight (even for me) and looks like a toy; The 55mm looks great, although i feel they can be loose sometimes (look good, but wear loose). I strongly recommend 55mm if you have to get these, unless you are buying for your kids.
4. Looks: They both look great, but I prefer the tortoise ones that are a little bit different but not too special. Another thing to note is that other people can see your eyes more easily through the ordinary lenses than the polarized lenses.
5. comparison to the OriginalWayfarer (2140): later I got a pair of 2140 (Original Wayfarer, 54mm, tortoise color) for my cousin. The Original Wayfarers are a bit more expensive, but feel they are of better quality: stronger metal hinge, thicker and heavier plastic. Size-wise, the Original Wayfarer...