Just last night I once again enjoyed the easiness of the Edirol R-09 as I recorded some thunder/rain with using just the built-in mic. I always have it with me and I'm really happy with it. I don't plan on using it for hi-quality SFX, but for example quickly recording things as they come along it's fantastic.
You can check this clip out:
Download.
The clip is in stereo/16bit/48kHz.
As for the MD vs. others, I prefer the R-09 over my Sony MD which I still own from my radio-days.