Ranked in these QuestionsQuestion Ranking
Pro Provides security and privacy
TextSecure uses an advanced end to end encryption protocol that provides privacy for every message every time.
Pro Free and open source
TextSecure is Free and Open Source, enabling anyone to verify its security by auditing the code. TextSecure is the only private messenger that uses open source peer-reviewed cryptographic protocols to keep your messages safe.
Pro Recommended by Edward Snowden
It is reported as his favorite chat app.
Con Signal requires Google Apps, which is privacy invasive
You first need to install closed source, privacy invasive Google tracking system into your phone by way of Google Apps, which gets access to everything that happens on your phone. Only after installing this Google Apps, are you able to use Signal.