I'm big on read/write segregation and explicit mutation. With simple signals you have this naturally. Once you move to a nested tree you can lose this. Keeping this control allows us to adopt immutability patterns and enforce unidirectional flow. To me this is the most sane way to deal complex reactivity.

I agree, then the way to read and update state with dependency tracing in solid seems meeting the sweet spot of the s-js and elm/react style.