I was able to make a short trip to the range today. My impressions of the P-10M:
1) Trigger is different from the P-10C and S, but honestly, not in any major way. My triggers are all originals from the factory. I didn't find the P-10M trigger to be a problem.
2) Holding the P-10M is exactly what you'd expect from a micro pistol. It is definitely different from gripping the C or the S. Something to get used to.
3) Lack of external slide release. This will take more getting used to. I'm really used to having one, and so not having one was a change. Again, given the purpose of a pistol this small, it is probably only a "range" issue, not an issue in real life should I ever need to use the pistol for self-defense.
4) Accuracy. At 5 and 7 yards, I found it to be somewhat less accurate than its bigger brothers. That may be only an issue caused by the fact that it is smaller and the shooter (me) needs to practice more with it. Having said that, all shots at both distances were on the target. My shots were consistently to the left of aim, so I need to adjust the sights.
5) Two failures to feed. I ran Sellier & Bellot hollow points through the M with no issues. S&B round nose had no issues. Fiocchi gave me two hiccups. One was a failure to feed while holding with both hands, the other was a failure to feed when shooting one-handed. The second case I will chalk up to how I was gripping the pistol. The Fiocchi was noticeable in that it was producing a lot of flame out the barrel. I didn't notice that with S&B. All in all, I ran about 150 rounds through the pistol, and the only 2 issues were both from the Fiocchi I had.
Overall, I am very pleased with the pistol. You give up some on capacity, but you gain some on concealability. There are times when I need to conceal more deeply, and for that the M is better than the S (for me at any rate).