I have the 1007XR and the sound quality is great but it has a terrible flaw in which it drops Bluetooth connectivity from RF interference. Same area on my drive every day and forget about using google maps going through Las Vegas, couldn't get it to work AT ALL in Las Vegas. It can be incredibly annoying.
Truck maps from Garmin on the DNR1008RVS, which have specific routes and info for large height vehicles (low bridges in the database, specific truck routes etc.), the DNR1007XR has regular passenger vehicles Garmin maps