For what it's worth, I have not been able to convince myself to go back to my Maxx. The two biggest things that have me favoring the M are the size and the UI. I love that I don't have to hold the home button to get my recent apps but instead a quick tap on the dedicated on screen button. Everything I want quick access to is just there. All the other things that matter have been equally as good with the M.
Reception: I have had one dropped call. This is in the same specific area that I can count on a dropped call (happens to be going under the stone arched train bridge by my house). Other phones I have had lose the signal in this area for about a mile stretch. Both my Maxx and M keep the signal until I go under the bridge and can immediately pick it back up again after I pass it.
4g/3g: I hold the connection with no laps at all. At home and various areas I visit frequently I only have 3g. Some areas are very weak 3g where previous phones are not able to keep a connection or have to try to hold the phone to the sky hoping to pick one up. Both my Maxx and M can always get 3g in these areas no problem. In the city is 4g. Have been there all week and no dropped 4g at all and is as lightning fast as my Maxx.
Display: the colors seem more brilliant and clear on my M. I also keep my display at 25% on my M where I had to have at least at 30% on my Maxx. Outside in sun, no problems even on a dimmer setting (Maxx always needs to be at 100% outside).
Camera: Sorry, I have not taken the time with this yet so cannot report.
Battery: Is shocking. It seems that 5-7 hours of on screen time is going to give me 17-24 hours on either phone. My Maxx has rarely made it past 30 hours (I don't go to extreme measures to save battery on either phone). Yesterday's M battery was surprising. See screen shots below...