Thank you! Ubuntu One is a buggy, laggy mess and frankly an embarrassment to Canonical. What would be neat is if they made a GUI for BTSync, and sold pre-configured hard drive space for it!
One time I needed to make something around 5 GB publicly available, and since Dropbox's free plan was too small, I used Ubuntu One.
Only after two days' worth of painful, oft-restarted uploading did I discover they require logging in to access publicly available files.
This is a mercy killing.