This looks cool ("150 CD's-worth of music"), but I wonder if using the cassette adapter to run it in the car results in significant degradation in sound quality or volume, or if there are any other problems. Any comments?

Sound quality is really pretty mediocre (I've got an 00 S4 with bose stereo, which is not very good to start IMO). In addition to the (sonically) compressed sound, muffled dynamics/transients, and less well defined imaging and timbre that one typically experiences with MP3s, the casette adapter makes the bass sound heavy and further attenuates the qualitites mentioned above. I can achieve comparable volume to the CD with either unit, but there is much more noise, particularly on MP3s with lower average levels (I find the noise intolerable for most classical music and some jazz, but I'm pretty picky).

I've tried two cassette adapters (Radio Shack and Sony) and get similar results. I haven't had a chance to listen to a Nomad Juke, but the Rio 500 had the best sound quality of the MP3 players when I last compared (including Nomad II). FWIW, most of my MP3s are 192 kbit CBR and used LAME or Franhaufer codecs.

CDs burned from the same MP3s sound much better, though still have some of these negative qualities compared to the original source MP3s. CDs burned from SHN files (lossless copies) are indistinguishable from the originals in my experience. I still use the adapter (particularly with my ThinkPad laptop, which has 13+ gig of MP3s on it at any given time) since its often much more convenient to build up an MP3 playlist and let it go than to switch CDs or make a mix CD, but you give up noticable quality in doing so.

To my knowledge, there isn't any easy way to get a line in to the symphony head unit and the FM tuners I've heard are pretty bad as well. Overall, I'd say its worth getting if you want the Nomad mostly for use outside of the car, but if you are looking for MP3 playing in the car as the primary function, I would suggest an empeg (www.empeg.com) or one of the new decks which plays CD-Rs with MP3s on them. The main downside, however, is that you have to swap out the stock stereo (I like the interior looks and am reluctant to put an aftermarket unit in).

What I'd really like to do is to build a computer for the car and hook it into an upgraded (speaker/amp) stereo system to play MP3s. I've spec'd things out pretty well (contact me if anyone wants more info), but need to get motivated and actually hack the thing together and program it.