Visual Studio 2014 is already much better.
http://blogs.msdn.com/b/vcblog/archive/2014/08/21/c-11-14-fe...
Last time I checked, outside most C++ compilers were still catching up with C++11.
There are more C++ compilers out there than just clang and gcc. Even those aren't 100% compliant at library level, if I am not mistaken.