Other FOSS product that tries to solve the same problem and which worked a little better for us. (We tried both)
Maybe the Jamulus folks can combine forces with Sonobus folks, implementing any Jamulus features Sonobus lacks.
The Sonobus UI is nice and responsive, coming from JUCE, but it's not native. More features, like metronome, are nice to have, but most musicians won't use them anyway as the instruments are usually connected through DAWs which provide all the necessary instruments for routing and layering sources.
The main difference is in the architecture, Sonobus is p2p, so it's great users have the option to try different approaches and find what works best for them.