I don't feel I have enough ground truth to know how good Kagi's search is in absolute terms (eg. there are plenty of searches where I still just "fail to find" and I don't know if it's my fault or theirs), I just know that I get less "junk" results with it than with DDG by far. With the additional ability to customize results and filters, I'd say it's a
good product and it's worth a small subscription fee.
The quality of all free search is just bad. Kagi, even when it fails, is basically the difference between me looking for something or just giving up and deciding it's not worthwhile. Kagi's not magic-tier like early Google was - it's basically just the only modern web search engine.