Well, after making almost as much of an ass of myself as dalethorn did, I actually have something useful to post.
I gave the T50p a listening a couple of months ago - gotta say I was quite unimpressed. I didn't like them at all. I wouldn't go so far as to say I'd prefer a buffalo fart over them, but... let's just say that I'd put them at under $50 worth in the sound quality department.
In terms of portable 'phones I was comparing to my Alessandro MS-1i - obviously a very different headphone, but portable nonetheless. I also had my HD 600 and the dealer's K701, DT 770 (much better as closed 'phones), DT 880, and a few others on hand to compare with. I tried various source/amps, from my Clip+ and uDAC up to the dealer's Beyerdynamic A1.
The bass and mid-bass seemed overbearing and uneven in response - and not well controlled, either. I'm not sure if I'd call it boomy; but it was unlike anything I've heard before and it didn't sound that good.
The highs were pretty nice - smooth and detailed without being overbearing.
The mids though - in particularly, the upper mids... Well, lets just say that it sounded like there was a gaping hole in the frequency response to me - and there is, of course, if you go check the measurement at HeadRoom.
There's almost a 20 dB increase from 4k Hz to 8.5k Hz. with the T50p. Also, in retrospect after looking at the frequency response graph, the "boomy-ish" bass and uneven response is probably the 300 Hz mid-bass peak and the dip just below the peak.
I was a bit disappointed in the soundstage of the T50p as well. Perhaps that's just down to expectations - the "air" I was hoping for that the Alessandros still provide (even if they don't do have much depth) wasn't even there.
I guess I'm really an open headphones kind of guy.
The build quality is, however, fantastic. The headband is amazing, although i don't really like the looks of the pivot or the cans. Regardless of the looks, they're still built better than any other portable headphone I've seen. The cable is super-thin as you all know, which of course doesn't necessarily mean a whole lot. At the very least though, the right angle plug is tiny and rather annoying.
Anyway, that's my quick impressions from a dozen minutes or so listening. I'm sure with more time I might have gotten at least a little more used to the sound signature - but I can already say it's definitely not for me.