5. Google Drive
Available on iOS too? Not yet, but soon.
One of Android’s advantages has always been the tight integration with popular Google Apps, such as Gmail and Google Docs. However, raw storage has been lacking. Drive integrates Google’s office suite (word processing, spreadsheets, presentations), along with up to 5GB of free storage. Drive also includes features that enable sharing and collaboration. Users can set policies to control who can access various files and what collaborators are able to do to them. You are also able to track all changes that have been made on a document.