The more I shopped the more appealing that controller became - for it's ability to be fine tuned to my riding. That and all the hyperbola surrounding the mid drives. I wanted to try that.
Once the decision was made on the motor, it was much simpler, as prior to that decision I was seriously considering building a GMAC based bike. I have a MAC 12t based bike now that I really like. The GMAC would be nearly the same with some cutting edge regen - which would work out well in the coastal area with rolling hills I spend a lot of time in.
M620 I received, is noisy, especially when compared to the MAC. Nothing terrible, but currently looking for some plastic gears. If I find them, that may be my first mod on this bike.
Best of luck! -Al
