I bought a
Kenwood Excelon KDC-X591.
Installation was pretty straightforward (if you don't order from Crutchfield, still buy the wiring harness, it'll save you loads of time and give you a removable connection, or else you can just splice the wires together).
I don't know how the quality compares to other systems, since the quality is degraded by the sound of an engine running, and tire treads hitting the pavement. It sounds just fine to me though.
It has a USB connection, courtesy of a wire out the back. I use a 2GB flash drive with it. It works just fine. Less than 10 seconds after the car starts, it's gotten acquianted with the flash drive, and starts playing. The joystick thing on the right controls navigation - up/down navigates folders, left/right navigates songs within the folders.
The menus are also quite extensive, allowing for lots of tweaking.
Cons:
- The blue lighting is really damn bright. I toned it down by opening up the faceplate, and covered the plastic diffusers with black permanent marker. I did the same to the surface mount LEDs.
- Hitting up/down to scroll through folders only moves one folder at a time - holding the joystick in those positions will not allow for rapid scrolling, though there might be a menu option for that.
I've not used the radio or CD playing features, just the MP3, and it works fine for that.
The faceplate is removeable, though reattaching it takes a fair amount of light (black plastic fits into black plastic) and careful alignment.
I'm quite satisfied with it - it is flexible in terms of what it can read with the USB connection, so I can feed it plenty of music, and never have to suffer through any god-awful radio commercials.