I use Kagi at home and Google at work, and IME Kagi results are much better compared to Google. It's easy enough to jump to Google by adding !g, but I never find myself actually using that... I do however end up doing the reverse, where I'll not find the result I'm looking for on my work computer and then quickly repeat the search on Kagi on my phone. I used to use DuckDuckGo on my personal devices before, and while it was mostly fine, I did have to jump to Google more frequently. In the end sometimes the results were better on DDG and sometimes on Google. I haven't really found any situation where Google results were better than Kagi (I do tend to prefer Google Images results, but I only very rarely use image search, maybe once a month).

There was also an instance recently where I was helping out a coworker get set up with something. I had done it earlier in the day, so I told him something like "type in $SEARCH_TERM, then go to the first page and copy the commands from there". He put it into Google, couldn't find the right result, tried a few variations, still couldn't find it. I pulled Kagi up on my phone, searched the same term, and slacked him the page while he was still looking around on Google.