I would not stake the future of my company on such a deal.
This is why I believe DDG is now using Yandex in addition to Bing for serving results.
The underlying question behind all privacy issues is that of trust.
In this particular case, the question is: Would you trust Google, a company that has delivered real value, has helped democratize access to knowledge at a global scale and has everything to lose if it was revealed that they are misusing sensitive information, or would you trust a tiny wrapper-company that claims to not store your personal information but actually uses a Russian search engine for searching ?
If you still went for DDG, what about when they decide to also use Baidu ?
Privacy is all about trust. I _trust_ Google. I do not trust a company that spends enormous time in smearing campaigns.