A few minutes ago, Google released their official Google Drive app on the App Store. We've since then downloaded the app and have put it through its initial paces.
What we found was a first offering that's lacking a whole lot of what makes other apps like DropBox great. You can easily view your files, but that's where most of the fun ends.
Sadly, you can't create new documents, or even upload photos via this initial version of Google Drive. The interface is decent, and the app seems solid from a stability perspective, but there really isn't a compelling reason to choose it over something like DropBox thus far...