Dropbox is similar to MediaFire in that it provides cloud storage, file synchronization and an Android client app. The difference between MediaFire and Dropbox is that MediaFire essentially lets you choose any file on your device that you want to be stored in the cloud. Dropbox, on the other hand, lets you choose a folder or folders on your device, and the contents of any file that change within that selected folder will be reflected in the storage cloud.
Dropbox allows you to store 5GB of digital media, whereas Mediafire allows up to 50GB for free. The premium plans for Dropbox start at $120 a year for 100GB, and go drastically up in price from there.