I'd also like to mention that you can't use the desktop client standalone and Signal requires a phone number to sign up. It would be nice if they got rid of these requirements.

I use Signal and Telegram both - it's clear to me that Telegram provides the better user experience. I like Signal from the privacy standpoint though.

If you're using Android then I think that Signal is kind of a no-brainer to use because it doubles as your SMS client, so if a contact is a Signal user you get the privacy you want, but if they aren't at least you can still text them.