Well, Pepe, Koss PortaPros have a lifetime warranty. Send Koss a copy of the receipt (I have a receipt if you can use) and they send you new PortaPros, no questions asked.
I also own a set of the 25th anniversary PortaPros, which have stronger magnets and have a slightly more peaky top end, which I of course enjoy.
Beats are made for and marketed toward folks in their late teens and 20's who believe that they are purchasing a top quality product simply because they trust the "Dr. Dre" name. Everyone on Cal U's and IUP's campus believes that the Beats Studio Pro headphones are the be-all-end-all of personal audio. One day I let an acquaintance listen to my MDR-V6's. He was blown away. I dare not let him listen to any of my "good" cans .
My guess is that Dr. Dre uses Sony MDR-V6's or 7506's in the studio, as most recording professionals do.
In the PortaPro price range, you can also get JVC HA-RX700's, which sound surprisingly adequate for that price point.