The upgrade to Google's iOS 6 Maps web app was revealed by AllThingsD, about five minutes into a video comparison between Android's Google Maps and iOS 6 Maps.
Walt Mossberg, who did the review, said:
"In fact, Google plans to announce on Thursday that it is adding its popular Street View feature, missing from Apple’s maps, to the Web version of Google Maps accessed from the iPhone and iPad. [...]
"I found the Android version of Google Maps to be not only better than Apple Maps, but also better than the iPhone version of Google Maps that Apple dropped. The biggest advantage over the former iPhone version, and the straw that apparently broke the camel’s back for Apple, was that the Android version of Google Maps, but not the old iPhone version, has long included free, voice-prompting, automatic turn-by-turn navigation. Apple added that ability to its Maps app."
It's true that turn-by-turn navigation was added to iOS 6 Maps. At the same time, however, Apple unexpectedly removed a number of things, such as accuracy, reliability, and more.
That said, Mossberg did find some errors in Google Maps. We ourselves found one recently, in which a business was said to be located at a different intersection that it actually was at.
However, the response to iOS 6 Maps has been so negative that Apple CEO Tim Cook felt the need to apologize. Google is known to be developing an iOS 6 Maps app, despite the advantage that Android currently has, as the company knows that iOS is a platform too large to ignore.