I have the "old" one and recently had a chance to AB it against a "new" one. Luckily for me, I could not tel any difference with my primary setup. I don't think there's any difference between the two. Source and amplification would influence the sound of the 650 much more dramatically, that's for sure. Do you know what he was listening out of?
Can't say I'm familiar with any of the equipment but it certainly quashed my suspicion that he was just running them out of his phone or something. I guess people must just have dramatically different tastes in sound the same as everything else. I was just a bit bamboozled to hear of someone being deeply disappointed with these cans.