Hey shanabit,
As a long-time user of the MR816x, and given my current needs…I can’t justify an updated module, even though my GAS kicks in often. Are you running into limits or problems? I’d love to hear them! 
I run Mojave on an iMac Pro with a lot of extraneous configurations (often testing midi input devices, apps, and firmware). I sometimes have to kill Waves processes, or restart a midi device, but that darn MR remains mostly solid in my torturous setups.