OK, just went down to Boarders and bought one (charging as we speak).
I was interested when I first read about it but then discarded the idea because:
1) I thought only work with memory sticks. Everything else I own takes SD cards and after living through the SmartMedia disaster, I'm not about to go with another format. Especially one from Sony.
2) It wasn't clear to me that I could use it to read other formats -- I have a bunch of books from Baen and others that I bought or downloaded for my Garmin iQue and I would want to read them on any new device. I also didn't want to be tied to Sony, because from the blurb I read it sounded like you could only get content from Sony.
After reading here I realized that these weren't true.
The big test will be next month when I make a trip to London (lots of reading time
)