I definetly experienced some annoying issues. I have an AppleTV in my car and now when I have AirPlay on if I'm listening to music and doing Nav from Apple Maps, anytime the Nav voice kicks in over the music, it disconnects the AirPlay. If I start AirPlay while in Maps, if I switch to music, it kills the AirPlay.
Also when listening to music the Volume starts off real low and then about 3-5 seconds into the songs the volume goes to what I'd say is about 125-150% of normal. Sounds horrible.
Lol why do you have an apple tv in your car?