Android/iOS: While Google Drive is great for sharing files, it's always been a little more cumbersome than it needs to be on mobile. Now that's changing, with sharing notifications and more mobile features.
The newest version of Google Drive, currently rolling out, will send a notification to your phone when a file is shared with you. This should be much easier than the usual email notification. You can also receive a notification when a user requests access to a file. Finally, Google's allowing users to preview Google Drive files that they have permission to view on Android without having to choose a Google Account. This should bring it more in line with how it works on the desktop.