I ordered the sage Mats Tee and another one that was on sale (no longer available). Both in medium (5,7 - 173lbs). They both fit and feel completely different. The Mats Tee is not soft or stretchy. Feels like a cheaper quality. The size of the shirt also seemed on the smaller side of medium. I ended up giving it to my kid.
The other shirt that I purchased seemed to be on the larger side of medium and fit loose but was nice and the quality was quite soft. Kept that one for myself. :)
Just be aware the fit and feel of the new shirts vs the old are quite different.