The m10 is a good recorder, but the sound quality has not been proven to be superior in comps here. A lot of assumptions have been made.
There is more to a recorder than battery life.
That's true, but I don't think most people who are recommending the M10 are saying it sounds better than all the others. At least I'm not claiming it sounds better and I don't think anyone posting in this thread has said that. Most of the good flash recorders sound pretty much the same to my ears, at least when you go line in with a pre. I can make flawless recordings with my MT1, but it's much more inconvenient and less intuitive to use than the M10, so I would not recommend either of the MT's (unless you need the digital in and don't mind the risk of it locking up).
The M10 has great battery life, a great display, the line in will take a very high level signal without distorting, the mic in is good, the plug in power will adequately run some commonly used mics without a battery box (though not many of the Church ones), and the internal mics (for those who may care) are pretty good.
I also don't think you can go wrong with R-09HR and a few of the other pocket recorders.
Still I think the M10 is gives you the most bang for the buck of all the small pocket flash recorders. That is of course just my opinion, which seems to be shared by quite a few others.