I'm still running the FM3 in 4CM with my Friedman Runt 50 and its really great - I'm actually using the Out2 4CM method which
a) gives me Unity to the FX loop amongst other things
b) free's up Out 1 XLR's for FOH purposes - this means FOH gets a nice, same every gig consistent signal which is independent of what the Masters on the amp itself are set - essentially a set and forget type thing (apart from possibly knocking the Out1 knob!!)
I am also running a PowerAmp Off Amp block as a sort of pseudo 3rd channel on the clean channel (using BE V1 Fat) to give me a lower gain version of my real Gain channel - you can't actually tell the difference between the 2 which is very cool indeed.
Totally hiss/hum free with no signal degradation, also running a Nux Midi Switcher (poor man's RJM!!) to change channels on the amp per scene.
My Kitchen Sink Preset has Vol, Wah, Phaser, Flanger, Drive, Amp Block, Pitch, Plex D, Delay, Filter, Cab Block - Can't really see me needing anything else, at this point the FM9 or AXIII would be overkill as a 4CM solution.