I have an alpine HU (CDA-9807 IIRC?) that my sister installed in the car and I inadvertently "inherited" when she bought a new car

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I personally am not a huge fan of the interface of this head unit ... it's rather limiting and I think trying to scroll text (as browsing an iPod's playlist) would be too tedious.
Instead, I bought the $20 alpine-input-to-RCA cable (still angry about how much that thing cost for all it does) and a six-foot RCA-to-1/8" cable. I snaked this wire through a hole in the dash underneath the head unit's location, and have my iPod rest in the parking brake cubby area. This way, I can very easily use all buttons and the scroll wheel by my right hand, and if I need to view my playlist I can quickly hold it up into view. It's also more versatile, because if I have a friend without an iPod then he or she could connect his device to my Alpine's input. I have a third generation iPod, whose touch-sensitive buttons are a bit too sensitive, so it helps to have it in one given location where I know where each button is and don't have to feel my way through the interface (as you would if it were on the passenger seat, in the cupholder, or in the glove compartment).
My 2c ... I don't think they've refined the interface enough to be worth the trouble of scrolling the playlists via the head unit.