Recently I have moved to Signal because, after the WhatsApp opportunity, I had to move my non-tech savvy family members to something better, and I suspect Telegram isn't it (I can't understand how it is funded, it is too "magic").
But it is rough, specially compared to Telegram.
For example: there's no way I'll share my phone number to chat with strangers, whilst on Telegram I have an anonymous username I can use.
But even forgetting about that, it is the small things, like it can't record and send a video (you can record it out of the app, and then send it from Signal; at least on Android), or the atrocious desktop app.
I'm happy it exists and I'll stick with it because they're supposed to be "the good guys", but I'm hopping it improves before I have to admit it was a mistake and I should have trusted Telegram.