I tried the Bing challenge, and changed my default search to Bing almost a year ago. According to Google I was performing 10k - 20k searches per month, so Bing Rewards was an appealing incentive. Over a years time, those are some decent rewards.
Bing results are very good. The notable exception I've noticed is for technical, geeky searches that are probably most likely to occur with this crowd.
The biggest problem is one of "branding" and confidence. At first I found myself searching Bing, and if I didn't find the result I wanted, I'd switch to Google. The results were often very similar. But instead of returning to Bing to perform another search, I'd do it on Google. As a Google user, when I didn't find the results I wanted, I'd try a new search... I didn't try Bing. When I noticed this and changed my behavior, I became more satisfied with Bing's results.