I don't think it's necessarily the worst, but certainly it's not as good as the other top dogs. As it's still pretty new, I believe it still has a long way to go. Google is still far ahead though.
Bing isn't the worst, nor is it the best. Actually Yahoo! is worst. You should see how silly it looks (the layout) - it's very bad. Bing is my 2nd favorite, it's much more faster and easier to use - and getting listed in Bing is easier these days.