The rewards are one. Granted, they're not huge (I also use Bing and find it amounts to about 1 $5 Amazon gift card per month), but if you find the result quality indistinguishable, it's enough. Also, like sremani, I want to drive innovation in the area of search, and while lots of people pay lip service to wanting more competition, putting your money where your mouth is by not using Google is the only real way to do that.