No doubt today SQL Server 2012 is one of the most power database, transaction processing & business intelligence platforms available on the planet. You talk about Public Cloud, Private Cloud, Hosted Environment or a Traditional Datacenter would will find SQL Server everywhere. Hybrid IT, Self Service BI, Enterprise Reliability/Scalability & Competitive Cost are one or the other reasons which makes SQL Server 2012 a primary choice for Customers.
Availability of migration tools, well versed partner led eco system, strong community, securing existing investments in competitors platforms are some other reasons which make this primary choice as "The Choice".
Usually, I am being asked to share resources which can help our Customers in making the right choice by understanding what difference does SQL Server 2012 makes while comparing it to the competition. Annexed are some links for your convenience:
1) SQL Server Licensing Value vs Oracle
2) SQL Server 2012 Give You More Out of the Box
3) Why SQL Server Might Be More Suitable for You than Oracle RAC
4) SQL Server 2012 helps deliver predictable and next-generation performance backed by customer, partner, and industry-leading benchmarks
5) Top 10 Reasons to choose SQL Server 2012 (reference links enclosed)
6) Comparing SQL Server 2012 to Oracle, IBM DB2 & MySQL (Case Studies, Analysts Reports, Feature Comparisons)
7) SQL Server 2012 in News & Reports
8) Reasons to migrate to SQL Server
9) SQL Server Case Studies
10) SQL Server Resource Center