I became aware of Intertia from a Ruby shop some time in 2022, who had good things to say, along the lines of "We could not ship as fast as we do without it." At work we are exploring Inertia to migrate parts of a long-lived Rails application quickly-but-gradually into an SPA. Have not gone live with the first feature yet, but so far a proof-of-concept and our exploration have been positive.
By "quickly-but-gradually", I mean that some pages will remain server rendered, and gradually more migrate to being browser-rendered, but each new page or slice of functionality is very quick to port over. If you have any sort of viewmodel, presenter, or form object abstraction in your server-rendering architecture, it is much faster to just turn that into JSON and use Interia than it is to convert everything into pure JS/TS and generalize a set of APIs to serve the frontend. Of course YMMV depending on your existing architecture and needs.
By "quickly-but-gradually", I mean that some pages will remain server rendered, and gradually more migrate to being browser-rendered, but each new page or slice of functionality is very quick to port over. If you have any sort of viewmodel, presenter, or form object abstraction in your server-rendering architecture, it is much faster to just turn that into JSON and use Interia than it is to convert everything into pure JS/TS and generalize a set of APIs to serve the frontend. Of course YMMV depending on your existing architecture and needs.