[jimmygrapes]

I am not anywhere near as familiar with the various XMPP specs and extensions as I am with those related to the Matrix protocol, but my general impression is that Matrix is much more flexible for things beyond chat and more willing to embrace emerging tech and communication concepts, while XMPP is more stable and focused. I'll need to get more familiar with XMPP before I can say more, but I can at least say that I have never got an XMPP server working AND had people join it, but I have been able to migrate many people to Matrix (albeit not easily), in large part because of the excellent work done on the clients (Cinny stands out atm).