Informix as A Decision Support/Data Warehouse Engine

We are considering licensing Informix at my company. I am curious about experiences others have had using Informix as the database engine for a Decision Support System / Data Warehouse. Has it worked well? or poorly? Are there any products that you recommend be either used or avoided in conjunction with the database - either from Informix or third parties? We would be using an Ultrix 4000 running Solaris 2.5. We would also be using the latest release of Informix Online. We anticipate having to keep using the latest releases of Informix Online in order to get the latest Data Warehousing features. Any insights or ideas? Do you think Informix Online is a good solution?