I'll echo that by saying that coming back to these from several days of using only the Skullcandy Ink'd and JVC Marshmallows (for review purposes, of course) I am reminded of just how good a $50 earphone can sound. Diminishing returns definitely do not kick in at this point.
At the moment, with Sony Hybrid tips, I am completely satisfied with the way these sound. I know I'll be less enamored with them once I go back to my RE0s or Etys, but they are a great reality check.
Hopefully soundmagic and its distributors will make good on their promises to the 2nd batch PL50 owners and the reputation of these phones will not be marred so early in their life.