I used duckduckgo when visiting China where google.com is blocked, its own baidu.com is useless for searching technical content, most developers need use vpn to visit google.com for development, but VPN is not a safe bet since the GFW keeps evolving and many VPN can not cope with that for daily reliable usage.

duckduckgo can do well in that market, better than bing.com and yahoo.com in most cases from my experience, but not enough comparing to google.com.