It's quite subjective, but my view is Matrix is what XMPP would like if it was written today.
The main advantages are it is using JSON instead of XML, and HTTP instead of custom protocols so it can work directly from browsers and with lightweight mobile clients. It also has a lot built into the core protocol, where as to get XMPP to do anything useful you will need to use a lot of extensions (and ensure the server and all clients support them).
The only con is it's still a relatively young project. I'm not sure I would want to rely on it as my main form of communication in a company just yet, but for personal usage it is fine.
The main advantages are it is using JSON instead of XML, and HTTP instead of custom protocols so it can work directly from browsers and with lightweight mobile clients. It also has a lot built into the core protocol, where as to get XMPP to do anything useful you will need to use a lot of extensions (and ensure the server and all clients support them).
The only con is it's still a relatively young project. I'm not sure I would want to rely on it as my main form of communication in a company just yet, but for personal usage it is fine.