We now have two published documents on Informix that talk about the positive impact of Informix in terms of the return on investment that companies can realize by deploying Informix. One of them is a Forrester paper titled "The Total Economic Impact™ Of IBM Informix Database Server" and can be found at this link It is an analysis of a 3 year investment cost vs benefit and validates what many of our Informix customers believe about and realize from Informix : "Less is More" - less admin requirements, less overall support costs, less impact during planned/unplanned downtime. It is based on the database server deployment infrastructure of a very large global retailer who have other database vendor products deployed and still sought to expand their footprint on Informix.
I encourage you to read this and present this data to your IT managers and/or other decision makers.
The other is actually a comparison of Informix vs Microsoft SQL Server done by ITG and the link can be found here.
n an earlier blog on what is now a non-existent edition - the Ultimate-C and which has now been replaced by Choice Edition, I did some comparison already on some of the capabilities of SQL Server vs Informix with some examples. This study is also based on a three year scenario surveying several midsize organizations in North America and Europe.  Some of the findings include : on an average 63% lower personnel costs deploying Informix vs SQL Server, comparing Informix Growth vs MSFT SQL Server Standard Edition for installations with 65 to 200 users, overall cost of Informix was 42% less than SQL Server, while for larger installations comparing Informix Ultimate with MSFT SQL Server Enterprise, overall cost of Informix was 31% less than SQL Server. These are substantial savings! Again I encourage you to read this and present this data to your IT managers and/or other decision makers.