I guess it depends where you live and radio signals. I tried the Zune FM transmitter with horrible results, I could not get a channel number that would give a decent signal, usually sounded like a muffled FM radio, stereo separation was minimal at best. I returned it to the store. Ended up replacing my car system with a Sony Xplod, not what I wanted but my factory system could not adapt to an aftermarket AUX setup and I did not have a CD changer, only single CD player. All in all I am very pleased with the setup, just a simple plug into the AUX input on the face and away I go...the sound is amazing but that is due to the Sony Xplod head unit. I have no power amp or sub unit and I get plenty volume and low end. I have not explored add-ons that would show what is playing on my Zune on the head unit display...not too much of a big deal.
Zune is AWESOME!!...since Nov 2006 Black30GB and Pink30GB (my wifes'!!!)