I lost an entire day of saves because "synchronize" to Ubisoft means "overwrite local files with what Ubisoft has regardless of time stamp" and not "make sure all files are current both locally and remotely" as it should. Turned that "feature" off, and because of how it works can never turn it back on or I'll lose my files again.
There's nothing this DRM "features" that is better than a plain DVD offers.