My thoughts after Photokina on the M and ME:
The M feels a little bit more weighty than the M9. I don't see it as a problem (though none of the digital Ms have, in my opinion, the perfect balance of size and form the film versions had) and the extra battery capacity is the reward (if shooting traditional RF style). The thumb rest is a welcome addition, it really helps.
The camera still retains the traditional RF shooting experience if you want it and the LV functions don't intrude unless you want them too.
As it was a pre-production model I am not sure how to judge the LV and EVF experience. It's definitely fiddlier and laggier. Maybe once the firmware is updated it will be a bit crisper. The camera is too heavy to hold mobile phone style, which isn't necessarily a bad thing! I didn't try the R adapter. For me I can imagine LV being of use occasionally for tripod shots, for instance to assist in placing a ND grad. The focus assist button on the front was hard to press on the camera I tried, maybe it will change by production time.
The led illuminated frame lines are perfectly good. It was a bit disconcerting to see no frame lines through the viewfinder when the camera was powered down. I don't think it is a big deal in practice.
If the sensor proves up to it, the 'traditional' digital full frame Leica rangefinder experience is safe. I asked about the presence or absence of an AA filter, and was told it has no AA filter as per the M8 and M9.
The ME: as expected very like the M9. Colour and feel of the paint not to my liking, not terrible, but black would have been so much nicer. Otherwise not much to report. Yes, the frame-preview lever is missing (as it is on the M).
Finally quickly on the MM: it looks great. All black is really nice!