My friends and I have used GroupMe (which is owned by Skype) for a few years now and some of us wanted to migrate due to privacy. We tried out Signal, but there were some major usability problems in you intend to use it as a "group chat" replacement. My biggest issue with it is that there is no mute feature for iOS. Yes you can turn off notifications at the iOS level, but I want the ability to only have @-mentions to have access to notifications.

I made us switch to WhatsApp instead as I think the usability/privacy balance was better (for our use case).