Much prefer astro.
It's somewhat counterintuitive, but the added complexity leads to simpler projects that are easier to maintain long term. I have simple markdown files, and a separate, code-based conversion process that works well for me.
Also the documentation for eleventy was always confusing to me. I almost got the impression that "it's so simple, we don't have to explain it". Whereas astro's documentation is much more accesible; there were a handful of cases where there was something I wanted to do and astro had an example of exactly that. I didn't have to do guesswork, just follow the examples in the way the creators intended. Stuff like that is important.
Astro is very nice, but I kinda feel like they are adding a lot of features I don't want and will never need. It's starting to feel too fancy for SSG. My first time using it I encountered 3 separate bugs with their compiler. The fanciness has a price.
Astro is great, and is what I prefer on new “static-y” projects (for more dynamic stuff, SvelteKit).
But 11ty really was so much simpler if all you need is to put together some templates, and don’t want to deal with component stuff. That said, the docs really are lacking in some parts.
Astro is fantastic. And with AI you don't have to deal with the piping much, just force it to have a reasonable opinionated framework at the base.
Astro is great, and easily extensible just by looking at the code and existing extensions too. Highly recommend it. Having the islands of actual react stuff is incredibly useful as well.