Earlier this year I have started a study, based on a survey I realized about Informix 4GL, in 2006. The first public release of the Informix 4GL study is available on this site.
About 100 people participated in this study, which created a very impressive quantity of data to process and analyze. The analysis covered many aspects of the Informix 4GL language, as well as vendors and their solution. I hope my analysis is correct and will help you in taking decision.
However, it fails important data about Gillani and their Informix 4GL-based CASE tool, FourGen. The study will be updated within a couple of days. If you want to be informed about the new release, shoot me an e-mail at jgp at jgp dot net.
The study has not been updated yet.