I found
a tweet today leading me to
a report (in Swedish) by the
Web Service Award regarding intranets among the largest corporations/organizations in Sweden.
The report, among a lot of other things, concludes that search in many intranets is "faulty" and that the end-user perceives the intranet as being "bad" because of this.
I would like to flip the question a bit; if there's not enough quality content to search through, of course the users will feel disappointed with search results. In Enterprise 2.0-adopting intranets, a huge mass of content is produced by lots of people compared to a editor-based CMS intranet thus improving the results when searching.
Maybe it's not the search engine that's to blame, but the quantity and quality of content?