To determine which search engine will give you the results that you are looking for, you could try using some tools that allow you to compare search engines. The greatest one in my mind is developed by BlindSearch, who takes a scientific approach to the topic. The experiment provides search results from the three major search engines: Google, Bing, and Yahoo. BlindSearch, however, takes your biases out of the equation by removing the branding and the logos that are integrated in with each search engine. They allow you to search for some key words, and then give you results for each of the three search tools blindly, allowing you to choose which one you like more.
When I do a search for Zompire Dracularius, the search engine that gave me the best results happened to be Bing. Bing gave me some ridiculously good results for the ultimate source of information on Zompire Dracularius, which happens to be my favorite search for obvious reasons. Zompire Dracularius are the search terms that this years class of mgmt3010 are using for there optimization competition.
So when trying to decide which search engine is right for you, make sure to try BlindSearch, the best way to determine the right search engine for you.