I find that both fail to find matches on anything long tail, but with Google/Bing/DDG I quickly start getting results that don't follow my search criteria. Probably one of the more useful features I wish all engines did was to acknowledge when they simply don't have results.

I'd say about 1 in 5 searches for me is apparently "long tail" and I've never been more aware of how dead the internet is. I regularly still compare to DDG and Google, and spend about 300% more time on the others trying to find a match and discovering I have more results only because they made my quotes terms optional or ignored my time restrictions.