I agree the T1 is very transparent just like the DT880/600Ω I had before it. I would say the T1 is neutral with a wide soundstage and gives an accurate representation of the recording. The T1 does not compromise, it can go deep and output plenty of bass which I like, but it can also go earpiercing high if that's what it gets from the source. Personally I like a warm sound and the highs somewhat tamed and smooth, thus why I use a tube amp to tailor the sound.
Anyway I think the only way to get a general idea of the headphones without actually listening to them, is to ask peoples opinions how it compares to a headphone you have heard. That way there is at least a common reference, one mans bright is another mans warm ;)