Google offers Navigation for free, and most people seem to agree that it is very good. However, it comes with one not-always-so-teency limitation: it only works if you have a data connection.
Fortunately a good alternative/backup is available, for a great price. Co-Pilot USA is a nav app that includes downloadable maps that can be installed in main memory (if you have enough space) or your SD card. This turns your Android phone into a full-time GPS, irrespective of whether you have a data connection. Co-pilot used to sell for about $30, and even that didn’t seem too bad, but in response to competing with Free, they have lowered prices, including a $5 USA maps option.
I’ve only dabbled with Co-Pilot, so consider this review far from definitive. But on my Captivate (Samsung Galaxy S), it works about as well as Google Navigation. It does seem to offer a number of features and configuration options, far more than Google Navigate. One which I am eager to try out is the detour functionality. I really think Navigate is missing a pretty important use case, which is–highway traffic jam, I’m going to jump off on the next exit, get me back on the highway in X miles.
Google Navigation still has some significant advantages because of the built-in integration with Google Maps, so it remains my default choice for around-town navigation.
One relatively consideration with Co-Pilot is space–Co-Pilot consumes about 1.5 Gb. So if you are operating with a first-generation Android phone (e.g., original Droid, myTouch 3G), you will probably want to have a 4 Gb or larger SD card. That Co-Pilot has more configuration options than Google Navigator is good and bad. The more option is good, the clutter and potential confusion is bad. They do have a “Restore to Defaults” option, which is a big step in the right direction, but you have to muck in the UI to find that, too.
Bottom-line–for $5, this is a very worthwhile tool to add to your Android toolkit.