I'm using it to keep copies of paperwork (for my job) on my tablet for backups in case my laptop ever decides to crash. Syncing takes longer than I'd like (I save often 1 minute intervals) and I've had the experience of documents not being properly synced being overwritten by older versions. That was a little frustrating (only happened once and I'm assuming user error of some sort). Other than these two things, I love it. No reliance on third-parties to keep data. Drag-n-drop files directly into tablet. No need to connect a USB cord or setup an FTP/SMB server on tablet or computer.
So, I've been working on documentation for a product. This is the first time anything like this has happened so it's not repeated yet. Anyway, I saved my document, only to open again it to the previous version of the document. I have the software syncing the document on my (android) tablet and (Ubuntu) computer.