[Tho85]

The underlying sync software (Unison) has been around for years now and is regarded as stable. So syncing should work just fine, although you should keep a backup of your files just in case.

You can also use Dropbox and Encbox together if you're unsure: Point your Dropbox installation to ~/Encbox and have Dropbox sync your (then decrypted) files. So you can be sure to have backups, file sharing features, etc. and see if Encbox is stable enough for you.

[aw3c2]

I often have Unison not notice file changes until I repeatedly scan or sometimes even until weeks later. If I new a better alternative I would not use it.

[Tho85]

They use some kind of heuristic to make change detection faster, see their documentation: http://www.cis.upenn.edu/~bcpierce/unison/download/releases/...

Maybe that's the root cause of your issues?