Besides GCC, Clang, and MSVC++, most other C++ compilers license the EDG frontend, so there's less heterogeneity than you would expect. I don't actually know if

Besides GCC, Clang, and MSVC++, most other C++ compilers license the EDG frontend, so there's less heterogeneity than you would expect. I don't actually know if there's another implementation of C++11 besides the ones I listed. Even Microsoft now uses the EDG frontend for Intellisense, rather than their own (more incorrect) frontend.