Google Maps for iPhone full review
Google Maps - what's missing
In terms of what's missing in Google Maps we can compare it first to Apple Maps. Aside from the deep system-wide integration of Apple's default map. Apple Maps works with Siri, and has access to your Contacts information so you can simply say (or tap) direct me to John Smith and it'll do the trick.
While Google Maps has a 3D function of sort, it doesn't have the same kind of office building integration that Apple Maps so the 3D mode isn't as detailed. Although Flyover can seem a bit of a visual trick sometimes, the 3D wireframe mode is particularly helpful at identifying your location via surrounding buildings.
Both have pretty decent traffic information, but Apple Maps also has detailed roadwork information (that is crowd-sourced via Apple's deal with Tom-Tom). This can make all the difference when driving, especially in urban areas like London.
In comparison to the Google Android version of Maps, there are a few missing features. Google Maps on iOS doesn't have the Layers menu, which also offers Terrain, Public Transport Lines, Wikipedia entries, and Google Latitude. Google itself has stated that Google Maps on iOS is better than Android, and in terms of interface and design it is: but there's clearly some room for it grow in terms of content.
None of these are really deal-breakers, and Latitude is available a separate app on the iPhone (or you can use Find My Friends instead), and we're sure that Google will implement as it moves forward.