While VS 2013 has much better C++11 support it's not close to full compliance. The Visual C++ team have decided to work on C++11/C++14 together which is slowing C++11 a bit.
Here's a blog post laying out their plans.
http://blogs.msdn.com/b/somasegar/archive/2013/06/28/cpp-con...
There's also a quite detailed talk by Herb Sutter on channel 9 as well. http://channel9.msdn.com/Events/Build/2013/2-306