A lot of people use file syncing services such as Google Drive, Dropbox, or Box and assume that this is sufficient protection from data loss. Although they do protect against a certain amount of protection for things like a broken computer or stolen laptop they are in general not a replacement for a real backup solution.
This point has unfortunately recently been made evident to a group of Google Drive users where some users have lost access to their data stored in the cloud syncing service.
The problem with syncing software in general is that if a file is removed on one computer all local copies are also immediately removed. In the case of the problem with Google Drive mentioned above it seems like an issue in the cloud service causing files to disappear and also removing the local copies of the files.
You want to make sure that any backup strategy you have is not vulnerable to a single point of failure and the file syncing services do simply not provide that. Using Underscore Backup you can set it up to create both a local backup as well as a cloud backup to be sure that no matter what happens there will never be any data loss with no single point of failure neither with your computers nor there would be a catastrophic event with the backup service.
