Well, I got the 505 yesterday, and it's all loaded up and ready to go. I also bought the cover with the lightwedge in it, and I have to say that it's all I had thought it would be, such a huge improvement over the other Sony readers I've seen, both older and newer, that I'm amazed that Sony didn't simply build on the 505 to put in more storage and a faster processor but keep the screen.
The cover with the lightwedge is much better illumination-wise than the side-lights in the 700, and since it uses it's own AAA batteries it doesn't impact the battery life of the 505 at all.
I had thought I might take advantage of the 700s note-taking and searching capabilities but I never really used them, so I don't miss them on the 505. And I never read PDFs, since I'm only reading fiction, so the poorer PDF capabilities of the 505 don't bother me.
Interestingly enough, though, the latest update patch I could find at the Sony web-site would have updated the 505 to version 1.1.00.18040, but my 505 came with version 1.2.00.18050 installed. I wonder why there wasn't an update patch to that version at the Sony site. . .
Anyway, I'm back in reader heaven again!