I guess that could also be because they have their peaks at different ranges, the HD800 is around 6-7 khz, and the T1 is around 10khz, so it is not that one reviewers are right and others wrong, is more that they are focusing on different brightness I think (or thats what I thought upon listening the T1).
Just out of curiosity, did you find the T1s bright? because for me they were far from bright and when I jumped straight from the HD800 - I thought they were dark...that is because I got used to the HD800. The HD800s have a nice way of, even though a tad bright, integrating its entire frequency range smoothly - a trait shared with the HD650.
With the T1s, one can really appreciate the tight mid bass, and crisp highs - to me they are more analytical, in a way, than the HD800. Analytical in that with the T1 one can break down bass, midrange and treble into separate entities very easily, and enjoy the individual merits of each in their own space. In this regard the HD800 is smoother and more musical - with a smooth, natural treble tilt - the downside being one cannot easily identify where the bass ends and midrange begins or when the midrange ends and the treble begins - just like in the HD650 (which used to be my favorite can).