I have only used an M-series machine so I am not qualified to answer the question. I am following the discussions about the attributes of various machines for when the time comes to make a replacement decision.
I have some additional criteria, a direct connect ability to 12 volts is high on my list of of features. The power here is not that reliable, and can be out for days. I also have a boat and 12 volt power is readily available there. I travel and the overall bulk, weight, and the quality of the travel bag for the machine are also important issues for me. Rain out used to be a problem for me, but I have found I don't need a humidifier. However, I normally do use a humidifier.
I can say that I have learned something form every response and appreciate those who have taken the time to share their views.