Would you like to put it on the 80GS ?
I really like the M-unit. But to be honest i don't know that much about the "other option"
If you would like to make the wiring simpler by using the M-unit you might have to lose some original features.
Switching off the indicators using the original switches you might have to use the on button to switch them off as well.
Using the clutch switch and neutral switch in the start system might add some extra wiring out side of the M-unit.
The same with the Relief relay ( if thats the right word) that switches off the head light when starting.
Besides than that I love the thing.
Maybe other inmates can tell you more about the pros and cons .
Good luck with your choice.
BMW R100'91/R80'93/R75/6 R80ST'83/R65GS'87/GasGasTXT300/DouglasW20-1920