The parrot Bluetooth is great, I put the mic on my steering wheel, so i'm basically talking into it, and sound comes out through the speakers, use it often at 60mph+ with no issues. I have an iphone 3GS and the connection is great, the parrot has music streaming so i can stream music from my phone via blue tooth to the car and easily navigate my contacts/playlists.
Sound quality, I cant compare to the aux in as I've never seen one, But the quality is much better then the Cd stacker or CD player in the head unit. I really rate it.
I listen to mostly electro/ Aussie Hiphop, so lots of bass n stuff, and I prefer the car to my Yamaha surround sound system! (I have the DSP 10 speaker system in my car)