While Astro has a lot of impressive features I found that it was the "developer experience" (god I hate that term) that was superior compared to everything I've tried before.
With Hugo and Jekyll I always needed to go revisit the docs whenever I hadn't worked with it for a while. I never got to the "oh, I get this tool now" phase, where the content generation could just flow without issues.
Publii was cool, but trying to shoehorn everything into fitting in the "Blog" model never quite worked out for me. Also being forced to work in a new IDE wasn't to my liking either.
Here are some of the things I love about Astro:
- The docs are great. You can read through them all really quickly. I tend to prefer systems that are simple to grok, and Astro is just that.
- The lightweight Astro components (https://docs.astro.build/en/core-concepts/astro-components/) were great for me, because they delivered on being able to create reusable pieces of code very easily (without having to touch React).
- Being able to generate part of your site from markdown and part of it from precisely crafted HTML is a great way to be able to handle both repetitive and unique content.
- The Astro themes (https://astro.build/themes/) are a great way to start. Find something that's somewhat similar to what you want to build and study how they did it.
This is obviously very subjective, but for me Astro was the first SSG that I really enjoy using, and that I didn't feel like I had to fight against.