R70x is a very different headphone than the well known HD800, T1, and the newer K812. R70x is not analytical at all, therefore, I won't use it for mixing. We will have hard time to apply de-esser using R70x, because it doesn't reveal sibilant very well. But I will use it for mastering due to its super linear tonality. And most importantly I will use it for music listening. R70x is almost colorless, very natural, with a little gentle roll-off on the upper treble.
T1 is one of the best headphone ever. I have both T1 and HD800 for many years. And I do prefer T1 for recording, mixing, and mastering. T1 as other high-end headphones must be match properly with proper amp and player. It sounds differently using different amps and DACs. You probably heard a bad matching. Once you heard a good matching of T1 and a good amplifier, you'll be amazed of what it is capable of. A friend of mine, a sound engineer, tested T1 with a simple DAC+Amp, and dislike it. But once he tried it with Audio-Technica AT-HA5050H at my place (check my signature for sneak peek), he was literally blown away.