I use my TomTom daily. It has free map updates, and have never had any map issues. It is great for driving because it has all the businesses at exits highlighted (i.e., is there a gas station or restaurant?) and you can search for almost anything, including Fedex drop boxes.

It occasionally gives me a route I know from experience isn't the best due to traffic, but it always gets you there and helps avoid missing exits. Mine has the realtime traffic update feature which has saved me a lot of time on several occasions.

I prefer to have my phone free for use as a phone or mp3 player.