What is the current state of C++11 support in major compilers (e.g. G++, clang, MSVC)
GCC C++11 status: http://gcc.gnu.org/projects/cxx0x.html
Clang: http://clang.llvm.org/cxx_status.html
MSVC is not as good. I don't have any links handy, but anecdotally it still fails to compile some of my code that compiles fine in GCC.
Here's the library features table: http://gcc.gnu.org/onlinedocs/libstdc++/manual/status.html#s...
Not feature complete if you take that into account, I'm afraid.
A little out dated but a good starting point. I'm using gcc 4.6.1 and am loving the C++11 features, only thing I've noticed it missing is implicit capture of this in lambdas.