I had to do the Violectric review first so it's going to take a bit longer as expected but each time I'm listening to the T70 it takes a while to appreciate the sound.
For my likes it could have had more present mids and heavier bass, but detail, layering and imaging are great. great clarity.
So in short it is the better headphone than the M50 qualitywise, but the M50 is the more fun one. The T70 is in no way an upgrade to the M50, they're too different. And I prefer it on a tube amp. I saw you're selling your T70, I'm going to keep on to mine for a bit longer but eventually I'm going to let it go as well.