My experience with DDG has been very similar to the one cited by aw3c2: I used it as my primary search engine for a couple of months, and eventually found myself always using !g, so I switched back to google.
On programming searches DDG goes better for me (than Google) because it uses the English data. Google insists on using Spanish data even though I disallow results in other languages than English or Catalan.
For other searches, mostly local information but if it's something recent too, Google goes better. So I use DDG at work, and Google at home.
I think the problem with tracking is not the intrinsic action, but rather the fact we call it "tracking". Tracking is the technique you use to hunt and kill animals. Showing Java results to Java programmers and C# results to C# programmers is a little different from that...