The alphabet has a way to balance the universe. While React was on the pointlessly complicated (not complex) side of the equation, Stapes is really minimalistic. Indeed, you wouldn’t know the index file belongs to a reactive app, or an app at all.
The controller, in turn, initializes the other components and binds the events.
The view is where the DOM tree gets touched, and that all happens with Zepto selectors. The role Stapes plays is minimal: it provides class facilities and a general approach to MVC.
Performance and code length were acceptable, and it appears that integration with other frameworks would not be a problem.
On the downside, the project is from the Cambrian explosion but hasn’t really reached the popularity you would expect. It gets about as many Google hits as Ractive, but is twice as old. Also, it has a paltry 2 tags on StackOverflow.