Tekdroid,
Thank you, Thank YOU! Very nice summary of some of the main differences between the units. I appreciate that you took quite a bit of time to list them.
I admit, I'm torn between the smaller M10 and just buying a replacement for the D50. Since I already have the Olympus LS-10, I have a lightweight, small recorder. But the dedicated Folder button and other options you point out make some strong points for the M10.
Again, many thanks to you and others for your thoughtful comments. It will make my decision easier.