I finally got a used dm-670, but I can't get it to sound as good as your recording. The stereo separation is nothing like yours. It's a stereo recording, but no matter where people are, left or right, it all pretty much sounds centered. I thought it was recording in mono for ages, til I tried rubbing the left and right mics separately and found it was stereo. I was also planning to use it as an mp3 audio book player, but it plays files out of sequence for some reason.
Thing is though, I got lucky and so far it looks like I got this item for free. It was listed as new, but when I got it, the box had clearly been opened before, the disc was missing, the batteries were installed and completely dead, and all the plastic bags looked crumpled, so there's no way it was new. I asked for a return, and the seller just refunded me the money but didn't send me a return label. I now have the recorder and the money back in my bank account. It's been a week and they still haven't sent a label or asked me to return the device. I'd probably be pretty disappointed if I'd paid the £65, as it doesn't really do what I wanted it to, but it's okay for free hehehe.