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.
Public - Group chats.
Dropbox - Online Sync and File Sharing
Chalk - Chalk is a calculator that tries to do right what others do wrong.
Google Drive - Access and sync your files anywhere
Slaask - Slaask enables you to set up a dedicated live chat channel on your Slack.
Mega - Secure File Storage and collaboration