@xanny In my experience XMPP is easier to administer. Prosidy basically just works while Synapse takes more effort and fuckery with the python env container thing so it doesn't break itself
Basically if you want more advanced features go with Matrix, otherwise XMPP
I mainly want the communities which are more active on Matrix but I’m leaning towards using XMPP with a Matrix bridge especially considering the huge amount of resources Matrix uses if your server joins large rooms.