Google Backup and Sync is very similar to Dropbox but there are some small differences. Google backup and sync has some extra options.

Desktop Folder Syncing

• Google Backup and Sync also has the option to make a backup of your ‘Desktop Folder’ and sync it.
• Dropbox cannot sync your desktop folder.

Sharing files on the web

• Dropbox makes it very easy to share files publicly from the finder of OS X. It’s is fully integrated into OS X.
• Google Backup and Sync makes it a bit more complicated to share files because it is still web-based. You need to go to your Google drive on the web and share it from there. (Once it’s set up it works well though!)

Accessing files offline

• Google Backup and Sync and Dropbox can both access file offline.

How to install Google Drive on OS X

What is the difference between ‘Google file stream’ and ‘Google backup and sync’?

What are the differences between ‘Google Drive’ (Google File Stream) and ‘Dropbox’?