I used it recently. Its actually really nice! Its fast. It also suffers from clients being weird. Although it is very stable. And extremely resource light. Apparently a single server can support 100,000 users or something. And it has distributed servers too (which is possible because it’s stateless. Wish Matrix had it though)
Matrix is in my (and a lot of other people’s opinion) way better for the future. The encryption is better, and there’s a lot more stuff supported by it. Importantly moderation.