Dropbox.com and box.com are online file sharing solutions and both offer free accounts for personal, non-commercial use. The free version of box.com offers 5GB of storage while dropbox.com only offers 2GB of space. But you can get 250 MB of additional space for each friend that you refer to Dropbox (up to a limit of 8 GB).
Box.com claims that* “82% of Fortune 500s manage critical content simply and securely with Box”*. It looks very similar to dropbox.com and has the same basic features but unfortunately lacks a desktop client in the free version. The mobile client is simple; it shows you a list of files and folders and a history of changes to see which files have recently been added or removed. You can upload photos and videos that you made on your cell phone directly to box.com and share the files via Email or Skype. While the app works fine it is very basic; the dropbox.com mobile app is just much more fun to use with its more modern look and fancy graphics.
The main advantage of box.com would be that it offers more space in the free version but they limit uploads to 25MB per file. Dropbox lets you upload 300MB via the website and has no limit if you use the desktop sync software. Box has further feature limits in the personal edition; document version management and their desktop client software (Box Sync) are only offered in the business and enterprise editions; Just uploading a file by moving it to a folder is something I really miss. If you like to password protect links or create links that expire at a certain date you also need to upgrade. So my vote for the personal edition clearly goes to Dropbox.
This short review only compared the free versions of dropbox.com and box.com. The business packages offer way more possibilities and in the case of box.com also features like the integration with Google Apps or Salesforce. But if you are only interested in quickly exchanging a few files just go with Dropbox (by registering via this referral link both you and I will receive 250 MB of bonus space).