jppelt
I am agreeing with others here: DDG and Mojeek are my favorites (reasonably private, Mojeek often has high quality results, and DDG's results are generally good enough if you aren't looking for anything too technical).
From what I've seen, the quality of a search engine's results will often depend on whether the topic is social, commercial, or technical. As a technical example, if an inexperienced person were wanting to learn about electric vehicles, the person will be shown countless websites that repeat the same misinformation that is socially popular (Google's #1 ranked site's claims are all-out lies). To get useful results, the user must insert additional technical words (i.e. 'stepdown transformer'), words that the inexperienced person would not know. Useful technical and informational websites are as if (purposefully?) hidden to the general public.
All search engines are able to list amazon.com and the common news(gossip) sites, but the better quality sites for technical and professional information were more commonly found on Mojeek.
From what I have seen, Swisscows is copy-pasting some of Mojeek's unique style of results, but when comparing their home pages' source codes, Mojeek is easily favored.