To me it's simpler and works better than Signal while being decentralized and federated. It has excellent clients for all platforms (and these keep measages in sync with each other) and does not require a phone number.
There's a fantastic one in the works, qmatrixclient (quaternion: https://github.com/QMatrixClient/Quaternion), but it doesn't support E2EE yet.
The developers badly need to invest in a UX engineer, but are currently stuck scrambling for money as their corporate sponsorship ran out.
I've also stopped using an IRC client and just use a Matrix bridge. Really happy so far.
Main drawback is that E2E is a bit clunky to set up, and downright confusing for non-technical users.