"Two months ago, Microsoft unveiled its revamped Bing search service, touting it as a "decision engine." There were some genuine new advantages which we did discover, but not everything appeared ready for Bing's first outing, and we were told to expect improvements to some features "in the coming weeks." Not months, weeks.

So this is August, and (do forgive me) what hath Bing brung? In our June series of Face-offs, the final score was Google (4), Bing (3) – not necessarily a runaway, but good enough for the champion to not feel immediately threatened. With Google testing improvements to its search engine, we wondered if we'd find any evidence of tweaking on Bing's side as well. We've decided to put both services through the same paces a second time to see which service is the one that's really gunning for a rematch.
...."

http://www.betanews.com/article/Bing-vs-Google-rematch-Whos-getting-better-quicker/1250282414