Remember when everyone offered free email? At a certain point, it didn't matter which one you picked because they were all free. The only differentiator was feature set, and for a while, all the freebies (Hotmail, Yahoo) looked exactly the same ... until Gmail shook things up and everyone else played catch-up.
To a certain extent, we have the same thing happening with cloud storage: it's space, on the Internet, to store your files. DropBox was revolutionary, but now there are fifty-seven* companies offering the exact same service. How bad is the market saturation? Here's a breakdown of your choices for free and paid service, respectively.