I find it quite annoying that you can't set the voice/nav volume relative to what volume the source is at. You have to set the voice/nav volume separately. Of course there's dynamic volume, but that's relative to what speed you driving at.
The reason it would be nice if it were relative to what volume the source is at, is when you have voice settings (mute/att/normal) set to normal. This way you hear the nav instructions over the music. And at the same time, the louder you turn your music up, the louder the nav instructions are.
Muting the music to give nav instructions every 5 feet is annoying. Att is a little more tolerable. But I like not having the music interrupted for a nav instruction, so I have mine set at normal. The only problem is the louder I turn the music up, the softer the nav instruction is. LAME! 
Oh well. More of a venting post. lol
If anyone knows if there are options I'm missing, please let me know.
I think these units could have had a few more options built in. Like trying to find a POI by city. I mean how lame is that? I have to save a search criteria to search by city? Wack. I think it gives the option to search POI around gps location, search criteria, and something else.
