I am a great fan of DDG and very much like all of the little nifty things which are so carefully introduced in it. But lately there is one thing which made me switch back my default engine to Google again.
Currently, I am searching for a lot of academic papers for my thesis as well as publication. When I search for a paper, DDG as well as Google find it. The difference between the two is that sometimes (quite often) DDG automatically (smartly ?) links directly to the PDF, while google links to the citation page (pubmed, IEEE, etc.) with as an "indented" search result the actual PDF. The problem is that most often you actually want the citation page. For me for the most important reason to be able to quickly import it into my Mendeley account (plugin enables to auto-import from citation page), as well as some other minor reasons.
Example of google:
I would love to either always link to the citation page hosting the PDF instead of the actual PDF, or similar behaviour as google (though DDG has no indenting).
Noticed this is actually a bad example as DDG does not link directly to the PDF in this case. ;)