I found DDG commonly does worse than Google on long natural-language questions, especially ones that are mainly made up of common words, and also seems to have more trouble than Google with automatically splitting queries into relevant noun phrases (like if a query included "vegetarian restaurant new york", I expect Google more reliably to decompose that into (vegetarian restaurant) (new york) than DDG).
But I'll keep an eye out and actually write down particular queries where I see these phenomena, and send them along.