I read many articles and posts over the last year or so, citing how great llvm clang is. On one side it shall have a static checker that makes lint redundant, and on the other side the optimizer has an -o4 where the -o3 shall be comparable to other optimizers. On top of that, compilation speed shall be really fast. And the part that makes it interesting for folks like Apple (who uses and contributes), is that it’s licensed under a BSD style license. What more could you want?