These are great Torrent search engines because they search in a lot of good torrent sites.
These are THE sites that I'm using. The search in both of them is close to perfect IMHO. Whenever I'm trying a new torrent site - I'm looking for some rare torrents to test if the site is good, so those passed with flying colors.
It also can save from making the scripts for all the sites that they are looking in. Except BTJunkie, because they don't search inside the torrents in BTJunkie.