The 700 has a little better PDF support than the 505, so that might be a consideration for you. The 700 allows you to zoom in on pages without using "reflow". (The reflow option is also available.)
As I'm sure you've read here, the screen on the 700 isn't quite as crisp as that on the 505. I have a 505 and my husband has a 700. There is a definite difference, and I'm happy with my 505. My husband doesn't mind the screen on the 700, though--and it works better for him, because he has a lot of technical PDF documents on it and he appreciates the zooming capabilities.
I agree with igorsk-- if you have a chance stop by a Sony or Borders store with copies of your books and try them in both readers to see which you prefer.
dordale
