For the uninformed Persols came out in 1917 while Ray-Bans came in the market at 1937, however as of 1999 Luxottica bought Ray-Ban hence the similar styling, how ever majority of the styles that you see have been inspired from Persol. Give or take the most memorable appearence for Persol's (at least in my opinion), is in the original Thomas Crowne Affair with Steve McQueen, then later with the James Bond films, followed shortly, by Miami Vice. Now if memory serves me correctly Ray Baan's recieved sudden popularity in the movies Resovoir Dogs, Pulp Fiction, and Top Gun.
If you would go to a sunglass store sometime (I'd reccomend Optical Store of Aspen if you live in LA, and don't specifically know what brand you are looking for) you would notice that Personls, and Ray-bans have minute differences except Persols cost exponentially more, due to the fact that not all Ray-Bans are made in italy (and that is becoming ever so evident as Ray-Bans are becoming more and more popular today). While the subtle styling of the Persols and the oh so comfortable flexible thingy ma bob make it a winner in my book.
Yeah...
-victheslik