Interesting list of features for for llvm/clang, but it is unclear to me how this provides any advantage over gcc 4.8, or for that matter llvm+gcc 4.8. Have to admit that I haven't really had a close look at llvm/clang yet (due to rather fundamental shortcomings such as openmp), so clarifications are highly appreciated.
On the licensing issue, I prefer gpl simply because it makes eee-tactics much harder, and because it has proven more effective for community driven projects. Seeing how Apple misbehaved when they forked khtml into webkit, the fact that they are behind llvm/clang makes me very wary. It is not a matter of ideology, it is actually very pragmatic.