The free plan's storage is rather limited, but Dropbox is a great way to securely share files without having to worry about the email provider of the person you're sending it to. The desktop app and ability to save files directly to Dropbox without having to upload them manually is incredibly convenient
Dropbox is the solution to most companies fragmentization. Its a tool you can use no matter what type of devices or data you have. Also Capture is the best screen recording solution I have ever used.