Recently I moved my pictures and videos over to Microsoft OneDrive. I also use Dropbox but for my disk usage I found it to be a bit too expensive. With OneDrive I get 100GB for € 1.99 a month or 200GB for € 3.99. Which is already cheaper as what I was paying with Rackspace Cloud Files. An added benefit of using OneDrive is that you can choose not to download certain (big) files or folders.
After moving my stuff over to OneDrive I was in need of deleting the stored files in Rackspace Cloud Files. My application is supposed to be able to sync an empty folder to a filled container effectively cleaning it up. But as I never tested it with thousands of files it did not seem to work and the application simply crashed a few times as well.
Meet Cyberduck! It describes itself as Libre FTP, SFTP, WebDAV, S3 & OpenStack Swift browser for Mac and Windows. It also supports Rackspace Cloud Files (which is now based on OpenStack as well if I’m not mistaken). With it you can browse your stored files, add or delete them and even synchronize folders just like you could do with my app. I highly recommend using Cyberduck if you were using Rackspace Cloud Files Sync before.