Polarized lenses, while they do reduce glare, are designed to filter out reflections. This is good if you ride, say, next to water a lot.
Non-polarized lenses reduce glare or not depending on the quality of the lens. I've had some amber lens sunglasses that performed better than some polarized lenses in that regard, and some that would flare up like a lightning bolt the second the sun hits the lens directly. It's a crapshoot. That's (one of the reasons) why it's always best to try sunglasses in person.