The SanDisk Sansa c100's menu system is intuitive and organized logically. You can browse tracks by artist, album, song, genre, playlists, Audible files, and recordings. The only negative we noticed was the cumbersome process of sifting through 1GB of files on a four-line display with three songs showing at a time; the iPod Nano and its Click Wheel are much more efficient.
For a budget flash-based player, the SanDisk Sansa c100 series has a fair share of features, including MP3, WMA DRM (purchase and subscription) and Audible playback, a voice recorder, an FM tuner/recorder, and photo support. The FM tuner has a decent signal, and it features an autoscan function and 13 presets. The voice and FM recorder both capture in a low-bit WAV format, and quality isn't crystal clear by any means. Voice recording is below average, with copious amounts of extraneous noise and clicking sounds if you touch the device while recording.
As far as music playback is concerned, we had good luck getting the SanDisk Sansa c100 to work with subscription files from Yahoo Music Unlimited and Napster. The device communicates with Windows Media Player via MTP, but it can also be set to MSC or UMS for drag-and-drop simplicity, even on Macs. With low but perceptible background hiss, sound quality is decent if a tad thin, and the maximum volume is underwhelming. The five EQ presets (Normal, Jazz, Rock, Classical, and Pop) and the five-band custom EQ add a bit of warmth. We also noticed a slight background click when starting songs.
Additional features include a single on-the-go playlist, as well as slide shows and simultaneous MP3-listening and photo-viewing capabilities. Excellently implemented, the SanDisk Sansa c100's context menu button opens up a few options--such as shuffle, repeat, and additions to the Go playlist--when in playback mode, though we think it should include EQ options. Bundled accessories include a proprietary USB cable, a standard pair of earbuds, a lanyard, a quick-start guide, and a software CD with a full user guide.