Virtually every time I feel like I'm not getting good results with a particular query in DuckDuckGo, I switch to Google to try it (I otherwise never use it), and 90% of the time now I get nothing better. That did not happen in the past—Google was a reliable backup plan. Now my expectations are quite low.
I have no idea about Bing because I never use it, though my understanding is DuckDuckGo uses Bing as one of its data sources.
DDG is using bing as index. Though it tweaks its algorithm a bit. Using it instead of Google for this purpose is not something I'd advise. Duck duck go's goal is not to improve the search results but to make the experience more private.
I have no idea about Bing because I never use it, though my understanding is DuckDuckGo uses Bing as one of its data sources.