Right now search engines compete to make themselves better in terms of their results and different functionalities. The more relevant results, the better.
I would think that right now Google still holds the most searches in the world. Why? Well, they’ve never stopped innovating and they’ve never stopped improving their search engine algorithm. They keep on changing it – adapting to the trends of the internet and to the trends of SEO pracitioners (especially the black hat ones).
Yahoo existed even before Google and Google existed even before Bing. Now the three are competing. Yahoo has lost the throne to Google because it succumbed to the era of black hat SEO keyword spammers and meta tag abusers while Google has come up with a more intelligent algorithm to counter that. And as we can see, Google is reaping the benefits – in colossal amounts.
Try searching for the same keywords in all three search engines and chances are you get different results. Is one better than the other? Hmm… With some keywords Google might have the best results but with some, Bing or Yahoo gives you the most relevant ones. There is still no solid search engine yet to always show you the most relevant results you’re looking for.
That’s because so many people are looking for so many things everywhere. It’s the world in the internet and it cannot yet be fully intelligently indexed. I don’t doubt that it is possible, but right now we’re not yet there. There is still no best search engine when in terms of relevant results – although Google is the most consistent search engine for me(speaking from personal experience).
So if you’re looking for something in the net and you get crappy results from one search engine, try the next one – you might just get what you’re looking for.