according to its release page clang 3.3 (due for release next wednesday) is also C++11 feature complete and apparently has implementations for several c++1y features already.
And perhaps more importantly, clang is the only project with a full implementation of the C++11 standard library. GCC supports the language but libstdc++ is not all the way there yet.
gcc also has various c++1y features already, although I think different ones than clang.