I dont have the 555, but I own the 595, compaired to my A500's the 595 are better. The senn are more detailed, better mids/highs, but I feel the A500 still have better soundstage and bass (though slightly more boomy then the 595). The A500 are also a lot easier to drive, I dont use an amp for my A500s, but do for the 595s. Music the 595 are superior, but for gaming and movies, I do feel the A500 have the edge due to their bass. Though the 595 are pretty good in gaming and movies too. I also feel the A500 are more comfortable then the 595, but the 595 are very comfortable cans also.