Currently looking for the best iPad app for GPS with spoken turn by turn driving instructions and downloadable maps (suggestions always welcome). My iPad has full GPS but don't really want to have the screen on all the time as the unit will likely overheat and shut down. Figure I can activate the screen when needed and listen for directions the remainder of the time. The ability to have the iPad stream music is great. The battery life is over 15 hours in music only mode. Also acquired the necessary cables to do on-bike charging if necessary.
Not sure if it is the best, but I quite like it when using the iPad as a GPS device.
GPS Drive HD (More for navigating in a vehicle) and GPS HD (Resembles functions on a handheld GPS for say water/camping) by MotionX. I think both are like $2.99.
The only caveate to the one that gives driving instructions, it will cost you $2.99 in any month you wish to use the voice nav, or $19.99 for a year subscription. The 1st month's purchase is included with the apps initial $2.99 cost.
The justification to the subscription costs is that the data is live and always being updated; however, you can nav without the nav prompts in a pinch. So you pay as you use. I've only activated the voice nav twice since I got it almost a year ago. I tend to use the GPS HD app more, as it does a killer job of recording some of the rides we've been on.
The GPS HD app has more map sources to choose from, and both allow you control your music stream from within the app. With the updated IOS, that really isn't as useful as it used to be.
If you have seen any of the ride reports JCZ posts that I've been on, good chance I have posted a route map from this program.
Tons of features that may or may not appeal to you.
http://drive.motionx.com/ipad/overview/