i got mine from sennheiser yesterday and boy are they glorious. my first good pair of full size headphones ever.
cable is WAYYY too long for my needs though so I'm in contact with Toxic Cables to get myself a 6 foot cable; not for the performance difference but because i'm pretty bothered by this 10 foot cable.
anyway, these things impressed me most with good vocals. i started listening to a few fast songs but once i got to the slower ones with good vocals, boy did these things impress. even more so once i set my amp to high gain. i dont know nearly enough about the various settings yet, but putting it to high gain just made the vocals so much richer and the sound much, much fuller. it was a very nice experience.
will give further thoughts after some more listening.