Privacy is the main selling point for DuckDuckGo. The Google search alternative doesn't track your search history, the time or location of your search, or your IP address.
However, I didn't feel the privacy features at work a ton in my day-to-day usage of the product. Typically, privacy isn't an issue until it's an issue.
One cool privacy feature was the ability to see the number of ad trackers blocked on each website I visited. On theringer.com, for instance, DuckDuckGo was able to block 13 trackers for me.
Some buzz has been generated by DuckDuckGo's "bang" feature — essentially, keyboard shortcuts to top sites. Search for "a!" and it takes you to Amazon, while "yt!" takes you to YouTube.
I didn't find bangs particularly useful, as saved searches from your drop-down menu accomplish a similar, quick result without having to remember the actual shortcut.