i wish zoom mode on 650 would remain as you turn the page in a pdf. Right now it seems like you auto-exit zoom mode when you go to the next page, and have to invoke it again and zoom into your previous settings again.
unless i'm missing something.
btw, re: kindle DX and pdf's,
here's a good review from youtube showing both limitations and experience. It doesnt look like the DX solves all problems, tho i agree the 10" screen is probably key for technical books.