The free version, called CoPilot Directions [iTunes link] has turn-by-turn navigation, trip planning and 2D maps. You can download the whole map database over Wi-Fi (not via iTunes) or you can download individual states or cities to save space on your iPhone.
If you download the free version, you get a free, 30-day sample of the complete app, including voice navigation with street names, 3D views, and the ever important option to update to the full version. After 30 days users can opt to continue using premium voice-guided GPS navigation with a 12-month or 30-day subscription via in-app purchase ($19.99 and $2.99 respectively), or they can simply continue to enjoy free lifetime use of map-only, turn-by-turn directions.
CoPilot Directions sits alongside a feature-complete version called CoPilot Live North America [iTunes link], which costs U.S. $34.99 and allows in-app purchases of live services, like Traffic Reports, Gas Prices, and Live Local Search. We reviewed that version of the app and found it to be about average in terms of ease of use, accuracy of the database, and features. I don't see any way to update to CoPilot Live North America from CoPilot Directions, so if you go with Directions you are stuck and unable to recoup any of your investment. Potential buyers should carefully consider which way they go, because after a few years the subscription option gets expensive.
As a result, I think ALK has complicated, rather than simplified the choices for consumers. Even if you opt for two years of CoPilot Directions, it costs more than CoPilot Live North America.
The free version is fine, but without any voice prompts it's not the safest way to get from point A to point B.
CoPilot Directions also has run up a pretty significant negative score at the iTunes Store, with customers complaining mainly about the accuracy of the maps. Other were quite pleased with it, especially for the price.
ALK also offers versions for the UK and Ireland [iTunes link], as well as CoPilot Live Europe [iTunes link]. The app runs on the iPhone 3G and 3GS and requires at least version 3.0 of the iPhone OS.