[inigyou]

What would possibly differentiate a chat app?

[yeputons]

It works reliably and without surprises. Messages are not lost. No weird errors.

Features: easy to switch devices, including PC. File transfers. Video sharing. Audio-to-text conversion out of the box.

[Almondsetat]

E2EE? F/OSS? P2P?

[inigyou]

In reality, they don't, not really. The only important differentiator is whether your friends use it and whether you have to self-host a server to use it (which has a large impact upon point 1).