I'm also very comfortable with Phoenix and Ecto (and LiveView), and initially found Ash a challenge to wrap my head around. After working through the book and really keeping an open-mind on my next project, I've found it a real joy to work with.

Keep in mind that Ash doesn't really replace Phoenix or LiveView (or Ecto), but it's built on top of it. You can still use Phoenix and LiveView the same way you are today, and just rely on Ash to build your context for you and how you interact with your resources. So I'd say it "replaces" Ecto in that sense (though it's all Ecto under the hood).

For me, I'm building a native app with a GraphQL backend and it has been an amazing productivity increase. With Ash, GraphQL on the backend and React and gql.tada (https://gql-tada.0no.co/) on the front-end providing a fully typed experience, I feel even more productive than using LiveView.

As a quick example - I have an existing derived GraphQL endpoint with a query for getting a resource, and I can have basic filters and sorting out of the box from Ash (i.e. filter by status, sort by name, filter by date greater than X, etc.)

Recently, I needed to build a feature to support adding a tag to a resource. I modeled the relationships (join models, etc.), made the necessary additions to my create/update actions and without _any_ changes to my GraphQL setup, I was able to support filtering my resource by tag (or tags) basically for free.

Can I build that in Ecto directly within my Phoenix context? Of course, but I didn't need to - Ash derived that functionality for me, and built that in, with all of the necessary preloading through dataloader and all of that for me, so the queries are optimized.

Ash is a huge mindset shift, and I think it'd be tough to incorporate it into an existing project, but if you're able to start a new project from scratch, I really recommend you give it an honest try. Especially if you think you might need to have additional data channels (i.e. LiveView and GraphQL or Json API).