How Dropbox ended my search for seamless sync on Linux: I totally concur with this Ars review — Dropbox is amazing. It’s so smooth and fast, it pretty close to magic.
Dropbox synchronization is so fast that it feels almost instantaneous. After initial synchronization, it will send only the changes made to the files rather than sending the entire file every time. Dropbox also keeps each set of changes, which makes it possible for users to access previous versions of their files.
Dropbox, by Odeon. They’ve done studies. Sixty percent of the time, it works every time.