I'd certainly donate if this were to be useful to my workflows. $50, $100. It depends, but good tools are worth good money to me.
Geoff, my current setup has the MCU for its faders at its center, but most of my work is in fact done with other controllers.
2 Midi Fighter Twister knob banks(4x4 x 4 banks each), an X-Touch Mini (2 layers and I use
this script, 1 per button, to select banks on the two Twisters.
So far, none of these devices reflect the state of parameters they control. Bummer.
For the MCU I am most certainly after controlling send levels with the faders, creating my own custom map of parameters for selected tracks and doing stuff with the buttons, because I use almost none of them on the MCU with Reapers stock MCU control surface plugin.