I bought one and played with it a little. When my LSD2 was acting up I needed to try another phantom powering preamp, and it was cheap for this test. After that I used it at a couple of shows to see how it sounded. I'm planning to trade it to Chris Church, and hoping he will upgrade the components in the Nady and report back to us.
From what I can see, it's reasonably clean. For newbies who are using phantom power box > line transformers, this preamp is probably a significant improvement. I would say it's "personality" is pretty neautral. It's not bright, or warm, or any particular flavor.
I ran a comp one night for Assembly of Dust at Hampton Beach (8-23-07). I had 2 sets of Nak300s, one set Nak300 > AD20 > H120, and the other set Nak300 > Nady DMP2 > R-09. I did this test just so I could post results. Unfortunately most of the show is total audience chatter, so I didn't seed it, but here are a couple of sample MP3s. Draw you own conclusions.
http://joe.bouchard.com/nak-ad20-sample.mp3http://joe.bouchard.com/nak-DMP2-sample.mp3Hope that helps.