Finally, some people who experienced the pain that is GCC and had the time freedom to actually create a new solution on LLVM (which by itself is interesting technology).
Why do I say that about GCC, the most popular C/ObjC/Java/C++ compiler on the planet? Because the project was so huge and opaque that it was nearly impossible to change or tweak anything. The code and sparse documentation are monsters.
Of course, clang is coming from one of the only sources of innovation right now: Apple.