SQL Server is flexible and relatively straight-forward to deploy. It is fantastic that reports can be delivered via Report Manager without any additional license fees. Reports can also be placed on subscriptions with the Enterprise version of SQL Server. This allows different people to get the same report with data that is tailored to their perspective.
The product would be better if it came bundled with Microsoft SharePoint. Some of the more advanced business intelligence dashboards must be run through SharePoint (SharePoint dashboards, PowerView, etc.). We also found that SharePoint Dashboards are time intensive to design.
Getting back to the license costs, we have found SQL Server to be an effective tool at a very good cost. Compared to purchasing 2 or 3 other products, SQL Server is a very nice all-in-one package (SQL Server database platform - MS SQL, SQL Server Integration Services - SSIS, SQL Server Reporting Services - SSRS, SQL Server Analysis Services - SSAS). The educational discount is also very helpful for K-12 or Higher Education customers. Installation and deployment was relatively straightforward. There is a slight learning curve on SSRS, but easy to pick-up.
If you are looking at cost savings alone, Microsoft SQL Server will pay for itself when compared an Oracle/Informatica/IBM Cognos solution. In a direct comparison of one-time software fees and ongoing annual support fees, Microsoft SQL Server will come out much cheaper. I would also argue that the software features are similar between the tools as well - so you're not foregoing functionality to save cost. We have found that BI developers are also easier to find on the Microsoft platform - which over time - may lead to lower TCO.
What needs improvement?
It would be nice if the Report Manager portal interface were more updated. It is much nicer to deploy the reports through the "shiny" SharePoint interface, but it is not as integrated with SSRS as the Report Manager.
Oracle, IBM Cognos, Informatica
Which others did you consider?