I have both a navigation system in my car and a handheld unit. I absolutely love both. I drive a Lexus with the OEM DVD, voice-aided navigation system in my car. It's incredible. I really like the device and will never buy another car without one. By far, it has helped me get to more places (or get out of them) than I would have ever expected. I never look up addresses any more. I just punch them into my navigation system on the car and it takes me there. By the way, I find it lightyears more sophisticated and accurate than the Neverlost System found in most Hertz cars. My hand held is for when I am hiking, out of my car, or flying. Again, I won't ever do without that device either.