One other nice bonus is that the cradle packs a built-in microphone, which will let you use your iPod touch as a speakerphone for Skype, and take advantage of other apps like Shazam that require a mic. It doesn't, however, allow for voice entry of destinations with Dual's navigation app. Speaking of which...
SoftwareDual's NavAtlas app is a bit on the basic side, but not really lacking in any significant respect compared to a dedicated GPS device. You get full text-to-speech, turn-by-turn navigation, along maps of both the US and Canada, over two million points-of-interest and -- this being an iPod touch app -- the ability to play music while the app is running (although the interruptions can be a tad jarring). Perhaps the biggest downside to the app is that it's a 2GB download (and actually requires about 5GB of space for the install process). That's hardly an insignificant amount of space to give up, especially on a basic 8GB iPod touch, and it's not the sort of app you'll be installing and uninstalling whenever you need it.
In use, NavAtlas tried to send us down a one-way street and suggested a few inadvisable U-turns, but always got us to our destination and, in general, performed quite well. Somewhat curiously, Dual suggests switching off the WiFi on your iPod touch to speed up the GPS signal acquisition time and, indeed, that did seem to improve things somewhat in our tests. The app also boasts a few other advantages over a standalone navigation device, including support for pinch-to-zoom, and full integration with the contacts on your iPod touch.
Your software options don't end with Dual's own app, however, as the cradle will also let iPod touch users take advantage of most of the GPS-related apps that have previously been restricted to iPhone users -- including other full-fledged navigation apps. Things don't work both ways though, as the free NavAtlas app will only work with the cradle, and you can't currently buy a version that will work on the iPhone.
So, the device is a viable alternative to other navigation devices (with a few advantages of its own), but there's one significant issue we haven't yet discussed: the price. Originally intended to run $179, the cradle is now selling for a hefty $199.95, which is the same price as the 8GB iPod touch, and more than many standalone navigation units. There's simply no getting around the fact that it's a tough sell and, if we had to recommend a navigation device, we'd suggest a standalone GPS (assuming you don't already have a smartphone with a good navigation option). At a $100 or less, it might well be a different story but, as it stands, this one is for iPod touch die-hards only.