The iRiver S100's simple interface is built around a scrolling list of nine options, including the main Music, Video, DAB and FM radio choices alongside fringe benefits like the text reader and Extras (Flash games, basically). Each of these options makes a different background image pop-up, and you can select the images you want manually - if this all sounds like too much flashiness you can set them all to the same image.
This is where the visual pizzazz ends though, as the rest of the interface is more conservative or - in some spots - downright bad. Navigation of music is perfectly fine though, thankfully. You can browse by Artist, Album title, Genre, Playlist or Rating and scrolling through your library is mercifully quick.
The radio side of the device feels under-designed and, well, rubbish by comparison -even though it purports to be the S100's main function. The FM radio interface is one of the most rudimentary we've seen, out-simplifying even the most basic of phones. This wouldn't be bad if it was quick to scan for the right station, but it isn't particularly. Presets are also poorly implemented.
The DAB half of the S100 fares even worse. It looks nothing like the rest of the interface, cast in a sore-thumb light blue colour - and it bafflingly reverts to landscape mode for no particular reason (other than for DMB video-watching, which isn't even available in the UK). You can't change this either. The slick scrolling animation used in the music library and main menu nav is gone - the execution of the player's main feature feels like an afterthought and that's very disappointing.
Some respect is won back by the ease of use of the radio recording feature, requiring just a tap on the select button while in either the FM or DAB radios, but it's poor mitigation. There's no recording timer or EPG available, limiting the usefulness of this recording feature from the start.
The S100 offers an initially nice-looking front-end that can't cover up some dated elements at its core. You even have to manually re-scan your music library whenever you add new tracks - which will seem rather retro (and not in a charming way) to anyone who has ever used an iPod.