Thanks for the suggestion! I'm considering adding more libraries to the comparison page (Datastar and Unpoly are on my radar).
That said, µJS and Datastar have quite different philosophies. µJS is a lightweight AJAX navigation library (~5 KB); it intercepts links and forms, swaps fragments, and stays out of your way. There's no client-side state: your server renders HTML, µJS delivers it.
Datastar is more of a reactive hypermedia framework. It brings client-side signals (reactive state in HTML attributes, à la Alpine.js) and uses SSE as its primary transport: the server pushes updates rather than the client fetching them. It's a different mental model: Datastar manages state and reactivity, while µJS is purely about navigation and content replacement.
Both are small, zero-build-step, and attribute-driven, so the comparison is definitely interesting. I'll look into adding it!