Signal requires Google Play Services on Android. That means it's put simply not a privacy messenger. Yes there's crypto, but it's also tied into Whisper Systems' infrastructure, there's no federation. I use Signal reluctantly, and only on IOS.
Threema, which is popular in parts of Europe (and is what I use to an extent) is well established, but not open source, doesn't do voice chat or federation.
Wire is moving in the right direction with respect to being open source and having lots of good features, but is still not open source.
It's 2016 and our best crypto messenger options are worse than what we had 10 years ago when Skype was peer to peer, or Jabber with federation.
I can understand the reasons for not supporting federation, but I disagree. The Internet was built to be decentralised, literally to withstand nuclear war. A walled garden does not provide us with the redundancy or control the Internet offers.
There are other metadata related issues that pretty much every messenger suffers from but I'll leave this out of the scope of this comment.
What Open Whisper Systems and Wire need to do is open source the server components of their solutions, and try to remove the reliance on servers as much as possible. Only then will we have proper message privacy.