In my experience so far, DuckDuckGo’s search is good enough the vast majority of the time. Sometimes, its results are even better than Google’s, and they’re rarely much worse.
I’ve been using DuckDuckGo as my primary search engine on all of my devices for several months. I’ve had some speed issues with it (and still do from time-to-time) but the CEO of DuckDuckGo attempted to help me personally on Twitter when it happened.
DDG is vastly different than Google. Aside from DDG being completely private, one big difference is being able to build on top of DDG using DuckDuckHack.
Google, however, has a deal with Twitter so if you’re searching for tweets you still need to use Google. As I did for finding the tweet I linked to above.
I’d suggest giving DDG a try if you haven’t.