An attempt to provide a summary answer to the FAQ, "Sony PRS-505 vs Bookeen Cybook Gen3"

Contents 1 Similarities 2 Differences 3 Details 3.1 Sony's features missing on Cybook 3.2 Cybook's features missing on Sony

[edit] Similarities

• Both use the same Vizplex e-ink screen, just like Amazon's Kindle. No backlight, just like paper. Sony has 8 levels of grayscale, and the Cybook 4, but for reading, at least, this isn't noticable. (No idea if pictures are different, but that's normally minor at best.)
• Both can read simple PDFs about as well as any other 6" device, meaning "ok" at best. (With the V1.1 firmware, the Sony can 'reflow' the text portions of PDFs to improve readability, but how this works in practice varies from book to book.)
• Both have significant third-party application support, allowing eBook conversons to their respective 'native' formats.
• Neither reader can read from zipped files.
• Both will be able to hold plenty of books, but you'd probably not want to hold more than a few score at a time, as neither's indexes work particularly well when applied to hundreds of books.
• Both appear as USB Removable Drives, so can have their content managed by the host system's native file management methods. (i.e. they can both be used with Linux, Macs, etc)

[edit] Differences

• Sony:

  Multiple buttons (easy to hold/use one-handled/left handed, etc)
  Requires Windows to purchase and add DRMed ebooks from Sony Store or Adobe DE.
  Requires Windows to install firmware updates (updates supplied as Windows executable).
  Standby/Resume is instant and returns to the page being read
  Can be left 'on' continuously for weeks.
  Noticeably heavier at 250 g to the CyBook's 174 g

• Cybook:

  Dictionary support to look up words in books being read
  Easy to add/use different fonts
  Does not require Windows PC to add DRMed ebooks.
  Firmware updates are supplied as data file that is installed via SD card.
  Restart takes 20+seconds and returns to library
  If auto-off is not enabled, battery is drained in three to four days.

[edit] Details

[edit] Sony's features missing on Cybook

• LRF support including DRM (LRX)
• It has extra buttons and that makes menu navigation faster.
• Sony's LRF format can be richer than Cybook's Mobi. E.g. headers/footers
• Sony can read RTF files without conversion.
• Page number display when reading.
• Accurate page numbers tied to font sizes.
• Books can be sorted by Author or Title.
• Internal hyperlinks in PDFs are supported.
• Text reflow in PDFs is supported.
• 'Suspend' mode - it's possible to turn it back on and immediately continue reading.
• Appears to have fewer firmware issues. (Impression from the forum - delete if you believe it to be incorrect)
• Latest firmware supports ePUB and DRM PDF (ADE) format

[edit] Cybook's features missing on Sony

• Mobi support, including DRM.
• Dictionary lookup (only in Mobi books, needs purchase of a Mobi dictionary) (Available on SONY PRS600).
• Books can be sorted by file path (allowing implicit grouping by folders).
• Supports toggling of full justification and text emboldening.
• User TrueType fonts can be used.
• (Limited) direct support for HTML.
• Support for PalmDOC format.
• Proper support for font families (vs. "synthesized" bold/italics on the Sony).
• User can select any font in any of 12 different sizes to read a book (compared to three sizes on the Sony).
• User-replaceable battery (although to be fair, I'm not sure we're heard of any that have failed and needed replacing, so this is probably another non-difference like the greyscale levels.)