I'm new to njb3 and this board. I just recieved my jb3 on friday and couldn't be happier with it. I used minidisc for 4 years and am so glad to be done with it. I own two minidisc recorders in that time and had so many problems with dropouts skipping, setting levels, disc capacity. Who knows if the new Hi-D minidiscs will have these problems.
The big argument against the njb3 is the lack of mic in. So you need to use either a battery box/preamp or an external A/D converter.
Some people have been saying that the onboard A/D converter on the line in stinks on the JB3. After reading this:
http://audio.rightmark.org/test/creative-jukebox3-rec.htmland hearing it myself I disagree. While I'm sure it's nothing like having an external A/D converter, I suspect it's every bit as good as the ones found in a minidisc recorder. Let's face it, your external preamp is going to be better than the mic pre in the minidisc, and I just don't believe that sony is breaking the bank on the converters in their portable minidiscs.
Also if you get a refurbished njb3 on ebay your going to spend MUCH less than on a minidisc reorder.
My $.06