I've been a Signal fan since the days of Redphone/TextSecure but the biggest differentiating point for Telegram that I can see (other than a network effect) is

I've been a Signal fan since the days of Redphone/TextSecure but the biggest differentiating point for Telegram that I can see (other than a network effect) is the public groups. These are especially important i've noticed in Asia (e.g. Hong Kong Protests) and Latin America. Unfortunately one of the usages i've seen it popular for in Western Europe and the US is far right organising.