Signal is mainly used by the people I communicate with. The Founder of Signal is also a known Computer Security expert. The signal protocol itself is also used by WhatsApp, Google Messages and Faccebook Messages.
I just had a look at the telegram privacy policy (https://telegram.org/privacy#8-who-your-personal-data-may-be-shared-with) and compared to signals privacy policy (https://signal.org/legal/) telegrams policy is just not for me.