Light from the sun is for the most part evenly distributed. That is if you take a camera and look at any direction in the sky. Its light meter will have about the same reading. The reading will be different if you point your camera at the sun. I check this by standing with the sun at my back and looking through my camera at different parts of the sky.
Another thing about light is that. Light are small packets of energy that have wave like properties. Polarization allows certain light waves to pass while reflecting others.
If one was to take a long rope. Hold it at one end. And then move your hand up and down very quickly. The rope would make a wave like motion. The motion would be in the vertical plane only. But if you move your hand side to side you could make the wave move in the horizontal plane. Light moves along with the same motion. Some light waves are vertical some are horizontal. The truth it that in nature the light waves move along in a 360 degrees pattern about the center axis. Although reflected light that comes off a smooth surface tends to have a higher number of waves in the horizontal plane (glare).
Polarized sun glasses reflect the horizontal plane (glare) light. Some glasses will reflect all of the glare light. Some will not. Some will reflect some of the light that is between the vertical plane and the horizontal plane. Some will not.
All this talk and I have not even addressed the effects that different lens material has on color. Which will also effect what you see.
One thing that I can say for sure about any pair of polarized sun glasses. Is that they act on light the same way from either direction. That is if you glasses go a great job of reflecting unwanted light from the front end. They will work the same way for light coming in over your shoulder and hitting the glasses from the rear. Which in some cases can reflect a lot of that unwanted light directly in to your eye. Some sun glasses try to address this through design.
Long story short. All sun glass are not created equal. How much glare you see somewhat depends on you glasses. I use a pair of polarized sun glass here in the south west. I like them for most riding conditions. I don‘«÷t know if I would choose to ware them on rainy days. Or if my roads had lots of oil on them.
Tinted windows tend to separate the vertical light waves into their colors. Polarized sun glasses allow you to see those colors. When I ware my polarized sun glasses I tend to relax and enjoy the light show. Although I do notice some eye fatigue due to color separation after a period of time. I guess my brain doesn‘«÷t like seeing things that are a bit different from the norm.
You can try this at home. Take two pair for polarized sun glass and hold them one in front of the other. Then rotate one pair. The amount of light coming through the glasses should go to zero when the glasses are rotated 90 degrees to each other.