Google better then Yahoo?

What makes a search engine better then another? The amount of results you get back from a search?

Looking up "cars" on Yahoo came up with 803,000,000 results.

Looking up "cars" on Google came up with 409,000,000 results.

Mr. Fink said that Google was a better search engine then Yahoo, on his post made September 22th, and I wonder what criteria must be met to make a search engine better then another search engine?