I’m about to order something very similar, except with mach all the way through most likely. I was originally nervous about the arms because I previously had an ultrasonic and the as the sliding system slid up it would get caught on the shoulder flap if that makes any sense. It would basically hinder mobility and not let your arm slide all the way up. Just tried on the mach in store and had no issues with it what so ever. Protection was also lacking on the ultrasonic. Most likely going to go medium mach body and arms, beef up shoulders/bicep/forearms, and then make the forearms slightly shorter. Just tried on every chest protector in my local hockey shop and they had all of the latest models of every brand in my size (somehow). Mach was easily the most mobile and comfortable chest protector I tried on. We’ll see where it goes