For sure the mics will be cut-down. I doubt preamp will be.
I'm going to speculate that it has been. Looking at the specs, signal to noise ratio is 87dB as opposed to 93dB and THD is 0.03% as opposed to 0.01%. That suggests the preamps have been downgraded somewhat or it's the same preamps but just the byproduct of miniaturisation.
The internal mics don't seem to report much on their frequency response beyond their upper and lower limits. It would be nice to see just how flat the curve is. Otherwise, in terms of SPL, the M10 seems to have the upper hand there with 123dB compared to the D50's 120dB.
Cross-memory recording.
Something which would have been nice with the D50 but I'm happily using an 8GB MS-HC in it so that's sorted that out for me.
2xAA batteries mean battery life will probably be less than the D50.
Perhaps but depending on how much current it consumes at its lower voltage compared to the D50, I doubt it would be anything significant to be quite honest. Running time is not proportional to voltage requirements but rather current requirements.
Anyway, I'm excited. Sounds like good value recorder for the masses.
It does look tempting but I'd need to probably test one out before I decide to dive in. If the sound is at least comparable to the MZ-RH1 I used to have, then it may wind up replacing my D50 after all since it's a good compromise between sound and size. Listening back to my RH1 recordings, the D50 has left me a little spoiled in that regard and I've preferred it over my old RH1 in a big way. Otherwise, I'll persist with wearing long thick material shirts to hide the massive lump on my belt!