I have the DDX 616, which is basically the same unit w/o navi(which i hope to add later on
). The ipod integration is not bad, though sometimes ipod screen might freeze (other apps will work) and you'd have to restart it.
In the beginning I thought it took too long to turn on and start up, but now i'm pretty used to it and it doesn't seem so long anymore. The bluetooth/mic has been working well for me, never had a problem with it and people don't have problems hearing me.