I generally stick to Google for programming related searches and use DDG for the rest. Hopefully DDG improves to the point where I can use it 100% of the time.
Interestingly I switched to DDG because I was having to quote too many programming terms in Google. All of them sometimes, just to stop Google from autocorrecting. I still have 'g' wired as my omnibar shortcut for Google though as I don't always find what I'm looking for on DDG.
If it were possible to take Bing’s search results, throw a handful of people at them and match the quality of Google’s results, Google would not be where it is today.
That is the main problem I see with Duck Duck Go. The quality of its search results depends on Bing. Duck Duck Go can do things to offer something better than Bing, but not that much better that matches Google’s quality.
Result quality is only one part of the equation. Features is another, which is where DDG seems to be making a land-grab for. Users seem to be responding to this approach.