After months of posturing and reports of feuds between Google and Apple, Google Maps launched on the App Store earlier today. The app is already the number one most downloaded app on Apple’s marketplace, seven hours after it became available.

The app has been very well received, receiving a 4.5/5 rating on the UK App Store from 1,026 ratings (or 8,975 on the US store). It has ousted Apple’s own ’12 Days of Christmas’ app, as iPhone and iPod touch owners download Google’s new Maps title to complement or even replace Apple’s own.

Screen Shot 2012 12 13 at 12.36.05 730x327 Google Maps becomes the App Store’s most popular free app, just 7 hours after launch

The app itself includes turn-by-turn navigation, public transit directions and Google Street View. It also allows users to enjoy voice-based, turn-by-turn driving instructions and live traffic information from across the world. Google includes train, bus, subway and walking directions — bringing it up to speed with the Android and desktop versions.

If you haven’t had a chance to play with the app yet, why not read our full review.

Google also launched an SDK that gives developers a chance to integrate it into their iOS apps, bypassing Apple’s own mapping hooks and allowing Google Maps to power their apps, while also linking them to the Google Maps iOS app should they wish.

The NYT’s David Pogue notes that Google believes its iOS app is in some ways better than its Android version:

“The brand-new, completely rethought design is slick, simple and coherent. Google admits that it’s even better than Google Maps for Android phones, which has accommodated its evolving feature set mainly by piling on menus.”

Google is said to be working on bringing its indoor maps to the apps, as well as offering offline maps and a dedicated iPad app.

Image Credit: Justin Sullivan/Getty