I used Kagi for a few months, it was the best search experiemce I've seen, but in the end I decided I didn't value that enough. I use Ecosia now, it's fine- worse, but free.

I guess it's down to you how much you value web search. Kagi does have an AI tool as well, but I didn't use this and don't use AI search anyway, so can't comment on how it compares.