IBM Cognos is a sprawling set of products aimed at providing a complete BI solution for organizations of all sizes, but specifically large organizations. Unlike some other offerings that incorporate data mining and predictive analytics capability, Cognos is targeted specifically at the traditional reporting and analysis tasks using a variety of presentation techniques. These include dashboards, graphs, charts, reports, tables and so on. For organizations that have not yet implemented an organization wide solution to this need Cognos is a prime candidate. Perhaps the strongest feature is the ability of offer an enterprise wide, integrated BI environment. And you wouldn’t expect anything less from IBM, it does major on infrastructure after all. Having said this Cognos provides a necessary, but hardly sufficient set of tools to gain commercial advantage. It may satisfy the needs of administrative and planning functions, but provides very little opportunity to employ techniques for embedding intelligence into applications. For this users will need to embrace IBM SPSS as a separate set of capabilities, or some similar set of tools.
IBM has layered the Cognos products so users can start small and grow. The most basic entry level product is the free version of Cognos Insight. This is a personal reporting and analysis tool, which in the free version will access CSV files (nice as a taster, but not really practical). The paid for versions will access a much broader set of data resources. Cognos Express is targeted at workgroups and midsize companies, and Cognos Enterprise is the full-blown BI and performance management toolset. Over thirty other Cognos products are available to support infrastructure requirements, address specific needs, and provide additional means of data visualization.
What IBM Cognos offers is a platform for looking at what has happened, what is happening, and what might happen in your business. Every organization needs this sort of capability and IBM is one of half a dozen traditional suppliers (Microstrategy, SAP, Oracle, SAS) who offer a solution. However there are new kids on the block in the shape of Qlikview, Tibco and Tableau, although they typically do not have the tailored add-ons of the more traditional suppliers.
In summary there are no compelling reasons to choose Cognos unless the suite of products offers a particularly good fit with needs, or the organization has an existing heavy commitment to IBM products and services.