Cool piece. Looks like he's having a good time. How is Mega? I haven't tried it out yet. Is it worth checking out?
The Android app does photo backup too, which is one of the main things I currently use Dropbox for.
You shouldn't be. Their "encryption" does little more than provide them a way of saying "We can't comply with your subpoena because we don't have the user's key!"
Granted, Dropbox's security is pretty laughable too.
Your best option is probably to store e.g. a TrueCrypt container in either service. (Dropbox will only sync the parts of the file that change, so there's that. Pretty helpful if you've got a 1-2GB TrueCrypt container.)
One can assume that more free and open BTSync clients will appear in the coming years, at which point I will probably check it out.