Looking at my results today, I have good news and bad news, the latter in two trenches.
The good news is that this machine sounds damn good, playing back the DSD from the headphone jack, definitely great sound from a classical grand piano, in spite of the bad news, which is:
The somewhat bad news is that I can confirm Matt's findings on brickwalling. I was using a Josephson C617 with LD caps for the grand piano, at about 6 feet away. With low setting , the preamp overloaded (I now estimate you can't turn the volume below 10 o'clock without risking brickwalling, I had it around 8 o'clock). The sound on playback from the MR-1000 was not awful, but converting it to wav certainly loused it up. This may be salvageable with improvements to AudioGate, I'd hate to have to go analogue-out of the Korg to another recorder to fix it.
The really, really bad news is that in transferring the dff files to my computer I got a cyclical redundancy check error, and one file wouldn't transfer. This is something I've seen on badly burned DVDs, never from the hard drive of a 722 or a MiniR82. Playing that file portion back on the Korg, it burps at ~4 minutes in and repeats some measures four or five times, then gives me a hard drive busy error message. This was during the first of three files that recorded a Brahms sonata without any operator intervention, the second and third files are fine (except for brickwalling), so I expect that most of the first file is there too, if there is some way to fix the error at ~ 4 minutes in. Korg guy here?
Jeff