Kenwood ain't the best, but it ain't the worse eithier. Kenwood was much better years ago, like 10-15 years ago. If I put my own stereo in this car, it would not be Kenwood. Although, I am very happy with mine. It doesn't sound great at REALLY loud levels, but I'm not the type to have it on 30 all day long either. Usually around 15-20.
I've personally never had any issues with my deck. Although, I did loose one speaker. Replaced under warranty though, and that only took 5 months!
MP3's kick ass. I can't beleive you've never used it. Don't download anything less then 192 bit rate though, because it sounds like crap. I use a CDRW, and I just add songs to it as I need it. I've had the same cd since I bought the car. I'm not kidding. 1 cd is all I've ever bought since Sept, 2001!
I just erase it when needed, and start over. I would never go back to a cd changer.