I am using google for many years and I am too lazy to try other search engines if they was improved enough to compete google.

But from the other side, it is interesting to compare the relevancy or phases which my sites rank well in these search engines. Visitors comming from google and msn are comming from relevant phases (they will find what they are looking for on my website) but in yahoo my site ranks well for very unrelevant phases so I guess these visitors are not satisfied with yahoo search results.