Mostly right (I sold sunglasses a long time ago and still keep up with a lot of it). I would only buy: Oakley, Maui Jim, Costa, Persol, Revo, or *some* Ray-Bans at this point. Everything Luxottica is the same, except Oakley lenses are still a totally separate entity, Persol still uses their classic lenses, and Ray-Ban has a small number of lenses you won't find in the other brands (their tech series polarized for example). The other brands are still independent, and have made high quality lenses for a long time. I've heard good things about Randolph Engineering, but haven't ever owned a pair. I personally find Oakley frames the most comfortable, so I have more of those than the others.
And a lot of this goes out the window if you're looking at prescription (often you're not getting the brand's lens, only the frame, depending on your optometrist/insurance). I'm talking off the shelf lenses.