I have heard nothing but complaints about the Beyerdynamic T50p, which has awkward treble response; it's extremely peaky. Also, ATH-M50s are overrated beyond belief. Just flag them since people can't take a hint.
T50p's problem in the very beginning was requiring an hour to find the right position on the ear for optimal sound or it would sound like a dud otherwise. I have one with updated pads, it's a gem of a little portable headphone. Shame it didn't last very long before being discontinued. Its brother, DT1350. rules as well.
And the T50p treble is nowhere as peaky as ATH-M50 or Grado headphones.