As can be seen in the recently released Gartner BI Quadrant, Microsoft is leading in the ability to execute above all other vendors and also has a strong vision in BI. One of the main reason for this rating by Gartner has been due to the focus on Self Service BI (PowerPivot, PowerView), and yet still have the ability to migrate these solutions into a corporate BI solution (SQL Server Analysis Services).
For the full report see: http://www.gartner.com/technology/reprints.do?id=1-1DZLPEP&ct=130207&st=sb