I usually use dropbox folder just as backup. I work in my main project folder, and once in a while I copy the project files to the dropbox folder for it to be synced. I've heard multiple times that it's not recommended to work in a folder that's being synced. More so if the files change frequently.
Awesome alternative to dropbox, thanks for this. How is it for hosting images? I know that a lot of people link images from Dropbox as they don't have to deal with too much image compression when showing off larger shots of their work - I'll do a few tests to see how it works out.