Allthough DeepOnion is not the only one aiming high on security & privacy, my personal opinion is that they are the ones with the biggest community behind it that support the whole project.
They also expanded their DEV team to react even faster on the demands from the community and to make the experience of using their features nicer each day.
I've been using DeepVault for a while and this is a very nice feature that allows the verification of the documents in a very easy way... no unnecessary hassle to verify.
More things are to come so keep your eyes open people !