We’ve been burned on Google’s official Gmail app for iOS before, but after having been pulled mere hours after its initial release for being completely broken, it is now back with fixed push support.
Don’t expect any other new features though: there’s no multi-account functionality or anything else, just a simple app wrapper around the HTML5 interface. Google swears more features are coming, but at this point, we’re taking any of Google’s promises with a grain of salt.