'Google Maps for iOS is the best-designed maps app on any platform'
The majority of maps features that matter are all here: traffic, turn-by-turn navigation, transit directions, walking directions, satellite view, street view, indoor photos, Zagat restaurant reviews, and a bit of integration with your Google profile. Unlike many of Google's other, earlier efforts on iOS, Google Maps is a fully-native app instead of a "web wrapper." It also utilizes vectors instead of graphical tiles, which translates into faster load times and lower data costs.
Unfortunately, offline maps isn't available in this release. Google is doing some local data caching — in particular, transit directions don't go away when you're in a subway tunnel — but hopefully an offline feature will arrive in a future update.