I decided to go down the upgrade path, and went for this...
I previously had an older generation of Kenwood with an IP500 interface which worked well, but as with many adapters which present themselves as a changer to the head unit, it made use of the analogue line-out signals present on the iPod/iPhone dock connector. This is all fine but it means you couldn't use an Apple dock if you fancied going for a really tidy install without excess wires trailing around and an iPod randomly stashed. The Apple dock splits the line-out signal to a 3.5mm socket, away from the data connections, and is not passed through to the rear dock connector.
My new Kenwood connects via USB and doesn't rely on the iPod/iPhone analogue audio connection at all, and I can finally use a dock for the iPod which looks very tidy. Another bonus of the USB connection is you could use any old USB memory stick and the head unit will play whatever's on it. Which is nice. And on top of that it will charge any iPod that has a USB connection (early FireWire based iPods aren't supported unfortunately) up to and including the latest Touches and iPhones. No Scosche Passport needed...
Final icing on the cake for this particular head unit is that the backlight illumination colour can be fine tuned to your choice - 10 steps for each colour (red/green/blue) mean you can make the head unit look more or less OEM by matching the backlight shade of red to the rest of red interior illumination. Which is even nicer.
Everyone's got their own favourite brands but this is a cracking unit, not too dear at £130 delivered.
DubSteve