one of the big differences is that the nanos, razers etc all have flash memories. I have a 40gig that is an actual hard drive so its sensitive to bumps and drops ie: it will freeze up. They're not just for music. You can store large files, download podcasts, have your daytimer on it, watch video's, movies, tv shows you've missed, keep phone numbers, email addresses.... and the pest part, at least for me, is that Alpine makes car stereo's that will interface with it and control everything throught the deck. so no shitty FM transmitter sound. You can litteraly have 10,000 songs in your car, at CD quality sound.