Google Maps is the official maps app from Google, available at last on your iPhone.
After a hiatus of several months, during which iPhone users were effectively forced to switch to Apple's inferior Maps app, Google returns to the iPhone with an all new native app. The new version, a major improvement on previous versions - and arguably even on Android's Google Maps app - includes nearly all the features you could ask for, such as navigation, satellite, traffic info, street view and public transit modes. It's also faster, better designed and easier to use than before.
But the real reason we were missing Google Maps on iPhone wasn't Street View, even though it's great to have that back. The strength of Google Maps compared to its competitors is the sheer quantity of data it has about the world around us. Shops, bars, restaurants, theaters, landmarks... they're all here and most have a profile page with address, photos and reviews. When compared with the new Apple Maps especially, Google's app is by far the superior choice when it comes to finding a place and getting there.
Speaking of which, the navigation component in Google Maps is well designed and offers clear, easy to follow directions. For journeys by car, Google Maps includes information about tolls and in many locations, traffic info on its suggested routes. Living in a big city, I love the public transit mode which works really well and even lets me pick which forms of public transport I want to use. Street View completes the picture by helping me see what a place will look like when I get there.
Google Maps for iPhone isn't perfect, though. I'd like it even more if it had an offline mode which allowed me to store maps when I leave cellular coverage or visit another country. And while the app runs very well on newer model iPhones, 3GS users may find it a bit laggy. Finally, the voice search mode needs to be tweaked as I couldn't get it to deliver any useful results. But none of these qualms make Google Maps anything less than a 10/10 app.
In terms of design, usability, navigation and data, Google Maps for iPhone is easily the best maps app available for phones today. There are some small improvements that could still be made but this is as good an app as I've seen for a long time.