It's a very minor annoyance and well worth it in my opinion.
I was searching for a book quote for over a year. I tried every search engine, tried changing the terms, checking back several times every few weeks or so, but couldn't find anything even close. I tried kagi and it was literally the very first result on my very first search.
I haven't looked back and have never had an issue finding what I'm searching for since.
That really depends on your use case and how valuable web search is for your daily life.
I've personally tried Google, Bing, DDG, Brave search, and ChatGPT. Kagi is consistently able to find what I'm searching for more quickly and accurately than anything else, which has been very valuable for me in my personal and professional life.
It's easily worth the cost in result quality and time saving for me personally, but that doesn't mean the same will apply to you or anyone else.
As far as stand out features, there aren't really any that I can think of. It just gives me the results I'm looking for without any bullshit to wade through.