Here is the product release site for 11g http://www.oracledatabase11g.com/ As per Oracle communication it continues to be the undisputed leader in big data batabase category.
Some other product features/ claims-
The Oracle Database Machine and Oracle Exadata Storage Server use intelligent storage software to process queries in the storage layer and get answers at least 10 times faster than before.
Oracle Database 11g Release 2 drives down hardware costs by enabling consolidation in a shared computing environment—and reaping the price and performance advantages of commodity hardware. The edition based redefinition feature lets you upgrade applications while users remain connected to their business applications.
And interestingly
It includes numerous automations and advisors that help double database administrators’ productivity over previous releases.
Claims of 10X, and 100% productivity always enhance the statistical thinking in my head. Did the new software really do so much improvement or was the earlier release just plain daffy. Good software can rarely go up 10X faster and 100% more productivity in a single release.
However, Oracle continues to be number 1 as of now-
Two analyst firms recently published their market share numbers for 2008, both finding Oracle continues to lead the industry, topping Gartner’s 2008 Worldwide RDBMS Market Share Report with 48.9 percent share, and leading IDC’s 2008 Worldwide Data Warehouse Platform Software 2008 Vendor Shares report with 40 percent share.