Just download the ISO for free and burn the CD. Works like a charm.

The nav unit is actually pretty good. There are obvious drawbacks like the need to have the CD in the player in order to re-route, no color screen, and outdated map data. That said, I use it all the time in the Philly metro area and aside from the occasional "street that didn't exist prior to 2004" blips, it works very well. Routes are pretty direct, re-routes happen quickly, and the directions are easy to understand. I like that when you press in the left dial it gives you an arrival ETA.