Honorable Mention only.
Google Maps has been a staple on the Android side of the fence for years. In fact, it's so good, that there really isn't any need to buy or use any other navigation program on your Android device, provided you have what you need for a Maps-on-Demand app – 3G or better mobile broadband.
On the iOS side of the world, Google Maps is now also one of the BEST navigation apps in the App Store. The app was downloaded over 10-million times in the first 48 hours of its initial release. I think that speaks more to Google Maps' strengths rather than Apple Maps' weaknesses.
Google's strength is search, and Google Maps for iOS does local search very well. Google learned a lot about navigation from its integration as part of the Android operating system and they have brought some of that expertise to your iPhone or mobile broadband-enabled iPad. Simply put, this is an awesome app, and if you know you're going to be in an area with decent mobile broadband coverage and need a navigation app, Google Maps for iOS is an awesome choice.
I've used the app on both platforms. It functions the same way on both iOS and Android devices. Maps are clear and detailed; and its voice guided navigation is clear, well timed, and easy to understand. It's one of the best navigation apps I've ever used on ANY mobile platform.
Synching with your Google Account brings in all of your navigation history and favorites. If you've used Google Maps before, you're going to be able pick up right where you previously left off. The only thing missing is integration at the OS level, which might come with the release of iOS 6.1; but that is yet to be seen as of this writing.
Click here for Google Maps for iOS (US) on iTunes
Click here for Google Maps for iOS (Europe) on iTunes
App Type: Maps on Demand
Very readable maps
Google's strength is search