I used them for a while as well. Their search was good, and their auto-generated answers they provided was very decent. I loved the idea of non-ad supported search. For me, their problem was their value proposition. You could use search for free, but you have to pay them if you want them to index your github/dropbox/etc accounts, so they could be searchable from the same searchbox. I had no need to have any private accounts searched, so never needed those licensed features.