Late to the party here, but I think Oakley sunglasses and lenses are definitely worth it. By way of example, I recently bought some aftermarket, non-Oakley lenses to replace a heavily scratched pair of Flak Jacket lenses for low-light and night riding. While fine during the day, at night the discrepancy in the aftermarket lens quality and clarity is noticeable. They seem to enhance glare from street lights and other rides’ safety lights, usually resulting in me taking off the glasses half way through the ride. I consider this more dangerous, as we often have bugs smacking us in the face during the spring/summer, not to mention I also lose protection for any other objects or water kicked up off of our crappy, often wet roads.
My .02 says Oakley lens and construction quality are way ahead of most cheaper brands.