If you look at the top three search engines - Google, Yahoo, and Bing - all of them deliver very good search results. All are very impressive. And all do a good job with making search relevant and delivering results.
If you actually play with all three search engines, you'll find that Google does not do a better job of getting the most relevant results in the top three. In fact, often Google does a worse job than Yahoo or Bing.
But what Google and Yahoo do better is sheer scale and size. Google's index and Yahoo's index are MUCH larger than Bing's. my guess is that it could be ten times bigger. That means that Yahoo and Google will likely have much better results for longer tail (or more specific) searches.
For instance, as of today, Google has indexed 413 million pages on Facebook. Yahoo was indexed 214 million pages on Facebook. And Bing has indexed 125 million pages (even though Microsoft is Facebook's search partner).
For MySpace: Google (229 million); Yahoo (149 million); Bing (6.15 million)
For Typepad: Google (4.3 million); Yahoo (11.7 million); Bing (190 k)
For Friendfeed: Google (5.67 million); Yahoo (14.73 million); Bing (86 k)
For Lefora: Google (265 K); Yahoo (450 k); Bing (22 k) For GoodRec: Google (218,000); Yahoo (3,348); Bing (16,400)
After using the Yahoo search engine for the last few months, I personally think it gives the best results ... but it likely doesn't have the breadth of Google yet. Bing/Microsoft still has a long way to go (but they are on the right track).
