I have literally been listening for about five minutes to the T1, so it isn't burned-in yet, but I think this headphone is The One. I've been looking for something in the league of the Senn HD800, AKG K1000, or even the K701 is remarkable and worth considering.
My problem with Sennheisers in general is I don't find them musically involving.
The K1000 has a kind of grainy upper midrange and is too "cool" for my tastes.
The K601 is really musically involving, really warm (I like warm) and conveys the beauty of instruments, but lacks resolution and dynamics compared to the big boys.
The K701 has a "whispered EEE" coloration that I just can't take.
The T1 has what I am looking for: first of all MUSICALLY INVOLVING and BEAUTIFUL TIMBRE. And this is without burn-in even.
And it has the resolution and dynamics worthy of the big boys.
I'll follow this up in about 200 hours.