Android/iOS: The standard Google Drive app for mobile devices lets you view documents, spreadsheets and presentations, but doesn't do a great job of letting you edit them and can't work offline. Newly-released standalone Docs and Sheets apps solve both those problems.
The apps are available for both Android and iOS. If you open a document or spreadsheet in the current Drive app, you'll be prompted to download the separate apps. Google says a standalone Slides app for presentations will be released "soon". The offline mode is a particularly welcome improvement.
[via Google Drive Blog]