I’m not the person you replied to, but a lot of my friends that pushed us to initially use Matrix have grown unhappy with the direction it’s gone and really dislike the clients. I personally host a private Matrix server and I am fine with it for now, but I’m able to avoid most of the drama and bugs by simply not moving to the latest and greatest. I always liked XMPP in the past, but I haven’t used it in a few years. I am glad to see it picking up support and hope that some of the things I didn’t like about it (which I can’t seem to recall at the moment :) ) are no longer problems or at least may get some traction on resolving.
I’d take that page with a grain of salt, especially since it is quite old and not all of it valid anymore, but I agree that generally you hear the good things about Matrix. Even disregarding what that site has to say, I’d give XMPP a look. XMPP likely isn’t all rainbows either, but I like the traction it is getting and it did a lot of things right in my mind.