There are two different code bases called DropboxSync.
When the Dropbox module was first released in Pythonista v1.2, @wrenoud released a DropboxSync that was modernized by @sidewinder for Pythonista v1.4 https://gist.github.com/sidewinder42/8631794
In May of 2014, @DavidHutchison wrote a blog post about his own DropboxSync.py.
These are not derivative works but are instead two completely different code bases that share the same name. Pythonista Tools points to the first one and this is the one that I have used in the past but it has had issues especially as my library of scripts has grown. It uses dropboxlogin which simplifies the logic and setup process however it is a gist which makes collaborative improvement difficult.
I would be interested to hear which of these you are using and why.. Are there pros and cons to the two different DropboxSync implementations?