I have added Amazon CloudSearch to Open Test Search so we can compare it to other search technologies.
Check it out: http://www.opentestsearch.com/cgi-bin/search.cgi?query=enron
CloudSearch was able to index 48,737 (99.8%) documents in the collection. The rest of the documents was rejected because they, according to Amazon, contains illegal Unicode characters. The end user interface you see has been created by me in Perl.
The instance type has automatically been scaled up to a “search.m1.large” search instance, and cost 345,60$ per month (0,48$ per hour x 24 hrs per day x 30 days).