How Does Open Source Compare to the Proprietary Competitor?
Metric/Technology Server Operating Systems Business Desktop Operating System Home Operating Systems RDBMS Web Servers Application Servers Content Management Systems Source Control Systems, SCM Development IDEs Legacy Integration, Middleware, EAI Distributed Component Managers Programming Language Frameworks Office Applications Web Browser Any Random Need
Price Tag + + + + + + + + + + + + + = +
Market Share + - - - + + - + + - = + - - =
Innovation + + + + + + = = + = = + = + +
Free Puppy or Free Lunch? + + = = + = = + + = = + = + +
Support = + + - + = - + + ? ? + - = -
Service = = = - - - - - = ? ? = - = -
Legal Issues = = = = + = = = + + + + + + +
Mission Critical = = = - + = - + = - - + = = =
Usable by End Users - = - = + = = + + - - - = = -
Development community + + + = + = + + + + + + + + +
Licensing + + + + + + + + + + + + + + +
Resellable/Repackageable + + + + + + + + + + + + + + +
Vendor Commitment = - - - = - - = + - = = = = =
Fragmentation, version proliferation = = + + + + + + + + + + + + +
Maintainability, Customizability + + + + + + + + + + + + + + +
Bottom Line, Best Choice + = = = + + = + + = + + + + 0
"+ : Open Source is better" "- : not better" "= : about the same"
Notes
Why FOSS/OS? http://www.dwheeler.com/oss_fs_why.html
Vendor Commitment Computer Associates, IBM, Novell, even Microsoft (on a tiny scale), have released source code for community use and development. And a number of smaller vendors—including Chalex, Gluecode Software, JBoss, SugarCRM and MySQL—are built on an open-source foundation.

 -- http://www.cio.com/archive/030105/opensource.html
Free Puppy or Free Lunch? Open Source is gaining an edge in ease of integration and ease of finding knowledgeable engineers.
Legal Issues Probably Same or Fewer with Open Source
Usable by End Users Usability is similar on Linux, Apple, and Windows but Windows has a larger based of trained users.
Usable by End Users Open Source RDBMS systems have often better GUI tools than proprietary RDBMS's.
Licensing Open Source in many cases is far less of a licencing issue than proprietary. Some vendor licensing agreements are lockin and/or timebombs.
Fragmentation, version proliferation Historically OpenSource platforms have had much better longevity and backwards compatibility than proprietary solutions - which often truncate support after two versions and often totally restructure products.