[Demcox]

Try Session [0]. Decentralized, no phone numbers and adding contacts is done by either sharing your ID or an QR-code. It works well but, at this time, only texting. Does have pretty apps for iOS/Android and most desktops OS's

[0]https://getsession.org/

EDIT grammar

[Rayhem]

Has session had a proper security audit anywhere?

[chaxor]

Session is fantastic - definitely the best messaging system I have seen so far.

Signal in second place due to the phone number tracking and non decentralized status stated above.