Sound: Good base, of course, also depends on the Headset.
Operation: I like that I can charge the audiobooks from Audible by the Manager quickly and easily. All other audio books and music are also problems eg with the Windows Explorer easy to copy (with me Windows 7). The order is alphabetical by title. In Explorer, you can create or delete any folder.
By briefly pressing (li. Or re. Of Play) you can jump to de chapters, if you press longer one can correspondingly long-forward or rewind, which comes in handy when audiobooks.
What I do not like: Sometimes passages are repeated, ranging from a few seconds up to 2 or 3 minutes. That's when the new audiobooks from Audible, which are in fact already provided for this player, as well as been the case in several songs that are older and that I have converted to mp3.
Therefore, in any case, a star less.
PS: The supplied in-ear headphones was useless for me because he did not fit. Therefore could not test the sound quality.
Addendum on 09/21/2013:
The model (no. Beginning with SA4) is not compatible with my audio books City Library / eLibrary, an international distribution company. The predecessors to the no. SA3 but already. Funny!
Have about those right who think that MP3 players have no future because they are being replaced by smartphones and the manufacturer therefore no longer invest a lot?
Would be a shame, because a MP3 player is still much better and more comfortable than a smartphone for such purposes.