OK, this is really a back-post. During our tests back in February, our system achieved amazing search accuracy: with three words search, we had 93% search accuracy. Note, this also means proper search ranking: target result is within the top three search results.
Like any other search engines, the more words used in search, the better job we do. Our five words search accuracy was at whopping 97%.
If you are interesting in the details of these tests, feel free to give me a shout.