To be fair, that same level of distraction can occur with any in car device, from the empeg to the simple AM radio. It is all a matter of the degree of distraction. Passive listening is still distracting (as proven by studies with built in speakerphones).

As with anything else, it is how you use it. I posted a link to an article about an Alaskan driver being charged with murder for (allegedly) watching a DVD while driving... I can think of nothing more prone to abuse / distraction than that, even with safety features.

The big issue is to use common sense and to be careful.