matrix-synapse(server) suffers from performance issues[1], dendrite[2], the replacement should be resolving that but is currently in beta.

Apart from that it integrates fairly well with other networks through bridges.[3]

It can be self hosted and it federates, which is a pro. Not too sure about audits and security, it has improved much, when I started using it (2019) they didn't have login throttling[4] and shortly after that were breached.[5] Much has improved since.

[1] https://github.com/matrix-org/synapse/issues?q=is%3Aissue+is...

[2] https://matrix.org/docs/projects/server/dendrite

[3] https://matrix.org/bridges/

[4] https://github.com/matrix-org/synapse/issues/1452

[5] https://securityaffairs.co/wordpress/83751/data-breach/matri...