I am too searching for some shared thoughts about this little device.
I've been watching some clips on youtube and, while convinced it might come very handy, on the other side the overall quality doesn't seem that good to me.
Surprisingly Mv1 doesn't feature 24 bit recording, but only 16 bit pcm like in very old devices. We also don't know how anything the external audio input. Sony's D10 or Edirol R09 HR audio recorder had a decent line input, capable of handling the signal coming out from an external preamp; don't know if MV1 shares the same circuit with D-10. The last had 24 bit anyway.
I really don't understand why new videorecorders equipped with decent audio come out so slowly now that videos are getting more and more popular. If you want to shoot a good clip you still need a decent camera, record audio separately and then merge the whole thing.
Handheld audio recorders came out in the past years to allow people to pull out nice recordings at an affordable prize; one could improve quality with an external mic and a preamp and even have xlr inputs.
I would pay 500 bucks for a videorecorder with an audio section like marantz 661 capable of shooting decent videos....but there's none on the market by now.