The user experience of Telegram is by far the best of all apps with the sleekest ui's and the native (electron) apps for all platforms. Moreover because of the lack of e2e encryption (on standard chat) all your messages are just there when you log in and are easily searchable. Telegram also has very nice channels and some excellent bots and a very nice feature to send yourself stuff you want accessible anywhere... But imo Signal is superior and has my preference due to its privacy focus. It also has a desktop app by the way and it works ok.

Of course Signal's server implementation is still closed but something like Matrix/Riot is too much to ask from "normal people" (like my mother and father who I got onto Singal with ease...).