I switched from Google search to DuckDuckGo about two years ago in an attempt to detach myself from Google just a bit. I still use Google's calendar, Google Plus, and pipe a number of email addresses into my GMail inbox, but I now rarely use Google web search.
There were two main reasons for this. The first was because I found myself using Google for a great number of different online activities, and I found the breadth disturbing. The second was because it felt awfully big brothery for Google to track my online activities like this and correlate them. I got a bit of a wakeup on this count last night when after listening to Boz Scags on YouTube, his album popped up front and center on my phone's Google Play store. DuckDuckGo does not track your search habits.
You may also have heard of the search bubble wherein Google search will show you results it thinks you want, leading to you finding only stuff that agrees with your current tastes and insulating you. Not great. You can also avoid this effect with DuckDuckGo.
One of my favorite things about DuckDuckGo are the shortcuts it has available. If I want to find images of minecraft towers, I can search !i minecraft tower. If I want to find information about Christopher Reeves on Wikipedia, I search for !w christopher reeves. If I want a movie trailer for Guardians of the Galaxy, I search !yt guardians of the galaxy. All keyboard - zero clicks. And if I really still want a Google search, I just use !g.