I used DBIx::FullTextSearch in a project where I mirror and index a political commentary website. I have found that oddly, the index is broken for certain words - I never had a chance to debug to find out why.
On an AMD K2-350, 230 MB of RAM, RedHat 7.3, running a number of services (my home server so it has a very light load), approximately 3,500 static HTML pages, the following queries took the following times:
+Linux +Bush (5 seconds)
inane (~1 second)
"Bloom County" (~2 seconds)
This can be found at:
http://www.bitbuckets.com/bartbot/
WARNING: Political Satire contained within!