Yes, I have the iPod2Car.
It's kind of clumsy to use, but I got used to it pretty quickly, and it's much better than the Pioneer interface on this stereo.
For example, selecting a new playlist requires pressing PRESET1. The display will show something like "F:PLAYLIST" (pressing SEEK left or right changes it to artist, album, genre, etc). Then PRESET2 to confirm. Now in the playlist, pressing SEEK left or right on the touchscreen or joystick knob goes up or down by 1. To get to the 51st playlist requires pressing seek right 51-times. Then press PRESET2 to confirm. Now it will display the name of the first track, giving you a chance to use the SEEK buttons to go up or down, or PRESET2 to confirm. After pressing PRESET2, the track starts playing.
The other preset buttons will control shuffle, repeat, and title display. I don't have those memorized. The title display shows the entire album and song name. The XM channel number is the currently playing track number.
A major benefit of it over the Pioneer interface is you can do all this browsing without interrupting what's currently playing.
Drawbacks:
1. Every time you start the car, the iPod starts out paused and it's necessary to press SRC to start playback. This bothers me the most.
2. They really should have added an "up by 10, down by 10" like JVCs do. Either that or made use of the direct numeric entry feature.
3. Going up/down has a little bit of lag, still much faster than the Pioneer interface though.
If they would take care of at least the first 2 issues I mentioned, I would be very happy with it. As it is, I like it better than the alternative, but it still leaves me wishing for more. Overall, it really does work great and I haven't had any problems with mine. I picked it up for $70+shipping on eBay. Although the seller promised it'd come with the necessary cable for Pioneer, it didn't and I had to eat $20.99 buying a cable from Crutchfield.