Kenwood HU: best interface??

[rustywheelnut]

I have a Kenwood KDC-W8531 in my car.
I currently connect my iPod with a cable to the aux inputs. However, this does not charge the iPod or disply track names etc on the HU.

Would i be better with a different interface such as:

Kenwood KCA-IP500
Denison Icelink plus

or something else?

I have read mixed reviews of the Kenwood interface so I don't want to take the plung and end up with something that doesn't work very well.

Thanks