This impression must partially be due to how you write your queries, and the quality of the natural language parsing in DDG/Bing (your query leaning heavily on that). I searched "ruby element in array", Rails not being a programming language, and I get the Ruby Array docs with the first result (which is what I would want) and the StackOverflow result for the third. On Google, the StackOverflow item is first and the Array docs are third for the same query.
In this case you and I think that our respective search engines are providing the better result.
If you ever find yourself wanting to fall back on Google's results, just throw !sp at the front of a DDG search for StartPage's proxied Google service (or !g if you absolutely must go to Google). DDG has many, many shortcuts for directly searching StackOverflow, GitHub, Amazon, Wikipedia, etc.
This is most likely that Google has more user behavior data than DDG. If enough people use DDG and click on the StackExchange link for that query (or similar queries), DDG will be able to get that to the top.
On the other hand, did DDG just use Bing API, and only Blekko crawls the web? Or do I get my search engines mixed up?
Personally I don't, but it should be noted that there are other indexes besides what you have mentioned. That said Samuru and Procog are pretty interesting.
For programming questions, I almost always append site:stackoverflow.com to my search term... generally the anser is on SO, but I prefer the search engine's results over SO's search... on DDG and Google.
He said "I prefer the search engine's results over SO's search..."
DDG's bang notation uses SO's search rather than the search engine's results.
Note that DDG's bang notation is also redundant with Chrome and most other browsers that let you set your own search engine keywords. Chrome's is especially nice, just type the first few letters of the site's URL and hit Tab and you're in a site specific search. It works automatically for any site implementing OpenSearch (or you can add it yourself by right-clicking the search box), and you don't have to memorize any keywords, so that's two advantages over DDG right there.
That was discussed here some time ago and many people suggested explicitly omitting SO and StackExchange sites when learning new languages/technologies. The argument was that while the answers on SO generally get the job done, they rarely provide the context, depth and coverage the docs give. I happen to agree - I only hit SO when I don't know what exactly I need to search the docs for. It's absolutely great for this. For serious learning not so much.
Concise, but wrong: It keyed off of "find", so it produced a top hit of items related to that method (which means in rails: find in the database)
Now you could argue that I should have omitted "find", and there was a time where that was how search engines were used, but the fact that google got the semantics right is why it is first rate.
Still looks 2nd rate. I replicated one of my last searches (learning rails): rails find if element is in array
First hit on google is the stackexchange answer with .include? (which I was spacing-out on)
DDG yields the Array docs, which is correct but is a helluva lot of info when I'm looking for a concise answer.