I have minimal interference, but I guess it also depends on where your antenna is situated in relation to the iPod. The Vette is pretty decent since there's little metal between the two.
I'll say this - when you're moving, there's NO car stereo that'll sound good over all the road and engine noise. Plus, an MP3 player by its very nature has worse sound than a CD. The iTrip, when used in my house, has great range (two rooms from my stereo) and sounds like a CD to my ear. You get variance in the S:N ratio based on the volume of the iPod, too. Too low, and you lose signal. Too high, and you get static. For my money, the iTrip is the best out there. I think the Apple Store sells them so you might be able to get a demo. CompUSA also has them on sale sometimes.
[RICHR]