I have been using SQL Server 2012 in production since SP1 was released. We are a small organization, however, and it is easier to make changes. My main motivation for upgrading (SQL Server 2008 R2 SE -> SQL Server 2012 EE) was to take advantage of Master Data Services, and that has worked out very well (though I went through a bit of hell getting it to work prior to SP1).
I am currently evaluating the BI features of SharePoint 2013, also running against SQL Server 2012. It was surprisingly easy to set up, relatively speaking. We may also decide to take advantage of AlwaysOn at some point.
Several production databases are still running on the old SQL Server 2008 R2 server, but only because we haven't taken the time to move them yet. AlwaysOn may provide incentive for doing that.
(Edit: old servers are SQL Server 2008 R2, not 2008 RTM.)