Using it everyday too at $work, also used Slack and Gitter (and FreeNode/IRC FWIW). Quite happy with the current Element UI. They have slowly added features and fixed issues. I tried a beta some time ago with... topics? Rooms grouped in some sort of topic I think. It was really buggy, but I forgot about that I haven't seen it yet. So I assume they are doing some A/B testing, trying things slowly and seeing what works.