David A. Wheeler has revised and updated his paper
"Why Open Source Software / Free Software (OSS/FS)? Look at the Numbers!"
David's excellent work has allways been appreciated by the CanOpenER crew. According to David, this paper 'examines market share, reliability, performance, scalability, security, and total cost of ownership. It also has sections on non-quantitative issues, unnecessary fears, OSS/FS on the desktop, usage reports, other sites providing related information, and ends with some conclusions.'
This paper is getting to be almost book size now and is well worth the read. David's work can be found HERE