Their search is lean. It doesn't feel exagerated by a lot of advertising optimization. It has the !bang feature that allows users to quickly refine searches. Though Blekko uses the /search-term which is also very useful. Back to DDG, their user experience (in my opinion) is better. Things are more clear and concise. Results for programming related stuff are very very good. In fact, if Nuuton manages to be half as good as DDG, I will have considered it a success. Not sucking up to anyone here, but I just love the damn thing. Been an user for more than a year.