Free or paid, we highly recommend that you back up at least your essential data   against theft, malware or ransomware, and natural disasters, not to mention user error. Even if you work online, a local backup is a lot quicker to restore. And this goes beyond PCs: We get a lot of emails asking how to get data back from a stolen phone—the users generally don’t like the answer. 

Speed: Speed, in many cases, is far more dependent upon your broadband connection than that of the online service, though the geographical location of the storage and the equipment in between can make a significant difference. Check the location of the data servers if speed is important to you. Or, just give the trial a whirl and see if you can live with it.
Most services encrypt your files with strong systems such as AES 256 before sending them up to the servers over an encrypted connection. The majority of products we tested also offer a private encryption key option. If you choose to manage your own encryption keys (basically the "key" that decrypts your backup), know that it is your responsibility to remember it. The online backup service itself will not be able to help you reset the password if you forget it. On the flip side, this means that no one (including employees of the backup service and law enforcement officials) other than you can unlock your backups. This is ideal from a privacy and security standpoint. Use a password manager to keep track of your private encryption key if you think you will forget it.