I've just got back from the local festival where there was lots of high-quality amplified music (for on-stage dancers etc), and some actual musical performances - and I am extremely pleased with the recordings on the Mic Pro. A lot of it was as loud as I would care to expose my ears to, but no distortion visible on the waveforms. The result will be on YouTube in the next 24 hours, link to follow.
Luckily when I accidentally knocked my Mic Pro from the magnetic mount I was using, while fiddling with my video camera, I realised at once, and managed to spot it in the night-time grass.... No harm done.
And - just before I left the house, there was a firmware update for the Mic Pro - and it seems they may have changed how the "processed" internal recordings are created. In my early tests some of the settings such as EQ didn't seem to do anything, and I think that's something they have fixed - I will test it shortly. But my festival recordings were captured using the "original" setting, and there's no change in the audio that I can hear.