For hosting common files it's ok. Also it is on Android too do, great to transfer files between your Windows and your phone. But if you want better security you have to subscribe a monthly offer.
Duo Security - Duo Security provides cloud-based two-factor authentication. Duo’s technology can be deployed to protect users, data, and applications from breaches, credential theft, and account takeover.
Dropbox - Online Sync and File Sharing
Trend Micro Cloud App Security - Trend Micro Cloud App Security delivers advanced threat and data protection for Office 365 and cloud file-sharing services.
Google Drive - Access and sync your files anywhere
Cloudlock - CloudLock is a cloud security solution providing enterprise class security solutions for data in the cloud.
Mega - Secure File Storage and collaboration