I’m more biased against Google than against Microsoft, and as mentioned in another comment, the search engines are proxies of the respective companies, so it’s hard to give an objective opinion.
Now, what I would suggest, trying to be as neutral as possible, is to test both and see which fit your needs more. After that, use mainly the better one and keep the other as a fallback option.
If you’re sticking to Firefox-based browsers, Waterfox seems to be the fork closest to Firefox without being controlled by Mozilla.