Here's a blind test you can use to see who offers the best results Bing, Google, or Yahoo. Without knowing which search engine they are from until you chose a result: http://blindsearch.fejus.com/ Try it, you may be surprised.
I changed my default engine to Bing, and I've had no reason to change it. I still use Google. Competition is good.
I don't have a dog in the fight, but I think there are some tough times ahead for Google. I've never understood the market cap of Google ($129B today). It doesn't take much for someone to change their default search engine. I've done it many times. Anybody remember search.com, dogpile.com, altavista.com? Despite their efforts into many beta applications, nothing makes money for Google like search. If Microsoft continues to improve, and Google sees their search share start to contract, they are going to have a difficult time keeping talent, and innovating.