Lots of options, but it depends on the user
Glad to see some new entrants in this area, and while I personally have access to more traditional services like iCloud and OneDrive, I'm still a heavy dropbox user. For me, although it is a paid service, after having dropbox for several years, for me it does exactly what I need it to do and works across platforms flawlessly. I find it's also easier to share files as many folks I know might not have access to other services (although yes, they could simply download from the link) so it makes collaboration easier.
For organizations, I definitely see Box picking up steam, although heavy Microsoft users definitely benefit from the free services with OneDrive.