I have the Axxess with the iPod and XM interfaces. Neither is particularly usable. With the iPod interface you will often get "NO TITLE" displayed on the screen. Oddly enough, if you select the playlist display, and scroll to the end of the text, then switch back to the song title display it will show the title of the song. Also if you skip forward a track, it will often skip two or more tracks at a time. And it has a tendancy to play the first 4 seconds of a song, then jump to the beginning and start over (just once though).
As for the XM radio... let's see... no presets, almost complete inability to change channels (hit channel up and there is a 90% chance it will jump to a random channel). Often once you switch to a channel, after a few seconds it will switch to the previous channel. At least the artist display works right.
And the biggest bug is that the Axxess system MUST be active when you turn on the engine. If you have the radio off or on CD or FM and you start the car, the Axxess will NOT operate. You will have to switch off the car and remove the key, put the key in the accessory position, turn on the radio, hit the media key to activate the Axxess, then start the car. I am **this** close to trashing the whole thing and using an external unit. Axxess (AKA Metra) support is a joke... and yes I DO have the latest firmware for the device. I think Axxess released this on the market without ever putting it in a car an using it.