I checked them out, and I didn't really like them as purely a search engine. But they do have potential, so I can see why Google is worried.
I am using Brave Search I have notices it uses "AI" in some of it's searches. It's called the Summarizer at the top of the search, "Powered by Brave AI". Occasionally I have been asked 'Get AI assistance for "search term"' with a Generate answer button.
I think if your search is for some generic, factual info ( history related or biology or geography or literature) and you do not have to search for results in the last few months, I like Claude quite a lot. It's easy to use and most results are comprehensive and useful. No ads or hundreds of possible answers to wade through. As with all AI make sure that you don't rely full on it (medicine, law) though for most generic searches of this nature I have gone away from Google.