A couple of months ago, I wrote a post suggesting that bloggers could basically ignore optimizing their sites for Bing. My rationale was that Bing/Yahoo generated such a small percentage of total traffic to a sampling of blogs that I analyzed that it did not really merit a significant effort. This advice is probably still appropriate if your target keywords are competitive generic terms related to topics along the lines of blogging, affiliate programs, SEO, etc.
However, a post I recently wrote that targets a "news" related item ranks on the first page on Yahoo (which is powered by Bing), while the first news page of Google is filled with nothing but links to mainstream media outlets. This result demonstrates that the specific keyword term you are targeting has an impact on which search engine offers better rankings. The increased weight the Google algorithm is placing on domain weight has tilted the playing field for news related queries so far in favor of main stream media that the results returned are nothing but a collection of plain vanilla sites.
The specific term that was targeted in the blog post was "Illinois State Bill 512", a piece of legislation that recently was passed out of committee for a vote in the Representative chamber. Check out the Yahoo links for the bottom of the first page of a news seach. The results include two WordPress blogs, a Facebook posting, and my Blogpspot post.
As the above results show, for keyword terms for which Bing and Google return differing results, Bing does matter to bloggers (or at least for post targeting news related keyword terms. Thus, the case can be made that if you are a blogger posting on news related topic, Bing is friendlier than Google.