It's substantially better than Google for what I do with it (mostly work-related queries). A few reasons why:

* It blocks all the GitHub and Stack Overflow copycat sites out of the box.

* I can add additional sites to the block list with two clicks.

* It up-ranks (semi-)official documentation like the Python docs or MDN over blog spam sites.

* I can manually up-rank sites (and even pin them to the top of the results) if I'd like to see them more often.

Kagi is awesome because where Google thinks it can guess what you want, Kagi gives you an easy way to tell it what you want.

I already have an extension that's allow me to block, or highlights results on Google or Bing

Kagi's better than Google for me. Proof is that initially I only had it set up as default search on one device but I've progressively switched them all over out of annoyance with crap google results. I haven't yet had to go to google once to finish a search I started on Kagi.

This is probably true for me, if we also say that 50% of the queries are orders of magnitude higher quality on Kagi.