I signed up to blekko long time ago. I love it because they have tools that every search engine should have. ( google I am talking to you)
Their seo tools are awesome.
That is the problem of blekko. It is too good.
Too many options are not good for non savvy internet user like my mom. My mom just wants to type something and get her result.
She does not want to learn those slash tag system. Personally, I love it but I am a geek. I have a coding feeling when I use blekko. ( love this level of control over my search result)
This feeling is good for me but not for the non savvy public. Those features are great but do not beat the feeling lucky by Google or the cute presentation by Bing.
I love it and I will use it. However, they will need a serious marketing plan because most people do not need a new search engine.