The S9 already sits up there with the Sony NWZ-S639F as one of the best sounding MP3 players of the moment, but it edges ahead by supporting two formats - FLAC and OGG Vorbis - that the Sony doesn't. Now, we all know that on a noisy train or city street it's pretty hard to tell the difference between FLAC and a high-bit rate MP3 file, but listen to the S9 in quieter surroundings and you can hear the sort of extra tonal detail FLAC brings to the party. Desire, from Talk Talk's classic Colour of Spring, sounds incredibly rich and complex, yet the beautifully recorded classical instruments, organs and guitars still ring through on a wide but still coherent soundstage Meanwhile, AC/DC's Back in Black sounds as mean and hungry as it does on CD with a decent pair of cans, that colossal riff done full justice by the S9's command of the mid-range and bass.
The S9 is without doubt a great player - the hard thing is working out where it sits in the current pecking order. If you're mostly listening to compressed music on the move and you're not particularly fussed about video, Sony's NWZ-S639F is almost half the price for 16GB and easier to get a good sound from straight away. If you want an all-singing, all-dancing PMP with a slightly slicker interface (though no radio) then the iPod touch comes in for similar money to the S9. If however, you want a great sounding, good looking video, audio and radio player that can handle uncompressed music straight from your PC or media tank, then the S9 is probably the best choice out there right now. Just budget for some decent earphones and prepare to put in a little work to get the best results.
The interface isn't perfect, but the S9 is a truly great sounding player with a stylish design and a comprehensive feature set. Warmly recommended.