I am completely satisfied and have been able to find any serious weaknesses. The only thing that could possibly be improved, is to recognize and play videos.
I tried to MPEG-4 and AVC (H.264 / AVC) to transmit video and had been unsuccessful. Although the films are clearly encoded in this format, and I can also transfer, the player refuses to play. I have been a variety of formats in different codings tried to play, but to no avail.
Well, yesterday I and not have time to encode large today and try it on.
But this minor annoyance is personally not so tragic for me. My subscribed podcasts, also subscribed in iTunes to run without problems.
The transfer of the data, whether the Sony Media Manager, the Sony Content Transfer or Windows Media Player 11, and works just fine without any problems.
The Clear Audio 'Technologies really produce clean sound and the SensMe' technology is a good idea. So far, the title fit into the categories of SensMe 'more or less well.
The display provides sharp and excellent images. Although it is a little too small for real films, it is sufficient for entertaining video entertainment.
The operation is as ever very easy and you quickly to wherever you want to go. I find the menu structure much better than the iPod nano 4G or the Creative Zen. I had the others and would always prefer the Sony Walkman. The size and weight are great (light and narrow and fits comfortably in your hand).
The supplied headphones MDR-EX082 are surprisingly good fittable and deliver clean sound.
What might be missing is an AC adapter. But unfortunately, it's in many MP3 players like that.
All in all, I am completely satisfied with the Sony NWZ S 639 FB and put it quite clear in the first place!