Cheers! We've been running the various betas in production for a couple of months now. For our Rails app we replaced most of our Hotwired/Turbo with HTMX. For me at least, HTMX just makes more sense: you control the flow of content from the client, not from the server as you do with Turbo.
For pushing updates, we use ActionCable, but we do it in a different way from what we used to do with Turbo Streams: when a record is updated, instead of sending HTML from the server to the client with instructions on what to replace, we only send a small JSON payload with the ID of the element that was updated. On the client side, an event is dispatched that any DOM element with <hx-trigger="<resource-id>:updated from:body"> will trigger on. For the rest it's just basic HTMX, only the trigger is "custom".