Google has released a GDrive application for iOS and it’s pretty good. You can access all your files, search for them, share them with other people, preview them or open the files with other applications or download the files, so that they’re available offline. The image search feature is really impressive: it uses Google Goggles to analyse your images and associate them with relevant keywords.
The app doesn’t include the document editing feature from GDrive for Android and neither the file uploading feature. The Dropbox app has a better tablet interface, since it allows you to open files and still see the list of files in a sidebar. Dropbox has a better UI for photos and shows a small thumbnail next to each photo.
Hopefully, Google will improve the app, add the missing features from the Android app and make the interface a lot better.