Ask HN: Have you used MarkLogic Server and what was your experiences?

I'm considering using MarkLogic Server as a backend for searching XML documents for an upcoming project. I am wondering if anyone here has had an experiences with it and what they thought?

I'm considering deploying it as an Amazon EC2 instance and then indexing my documents into it from S3. Has anyone tried this?

Link: http://www.marklogic.com/products/marklogic-server.html