I am still looking for Dropbox alternatives. I wrote five days ago about trying Office 365 and OneDrive and today I will briefly go over my first impressions of Zocalo:
The setup was confusing: I used a "-" in the site name and the initialization process failed silently, never sending me a confirmation email. I removed the "-" (as a wild guess!) from the site name and everything worked. Zocalo is a beta service, so this is understandable.
A more serious problem for my particular use case is that there seems to be no support for "selective sync." On Dropbox, I save space on the small SSD drive of my MacBook Air by un-syncing folders that I probably won't need for a while. I like this feature.
The strong points of Zocalo are managing files in a work team or a family group. This is the great use case for Zocalo.
It really is not fair to compare Zocalo and Office 365/OneStore with Dropbox because third parties have had time to use the Dropbox APIs in their applications. As an example, text editors on my Android phone and iPad use the Dropbox APIs for live editing of compatible files. In time, third party support will probably be there for Zocalo and OneDrive.