[FullyFunctional]

I've heard this unsubstantiated claim for years now. It certainly depends on your metric. LLVM still lacks behind in generated code quality on most mainstream platforms [my own unpublished benchmarks]. LLVM appears to attract more mind-share from people leveraging the infrastructure, including writing new front- and back-ends; I'm guessing the code is easier to understand and better documented.

A few years ago I had expected LLVM to have caught up to GCC by now, but I hadn't anticipated the accelerated pace of GCC improvements. I don't know if the competition from LLVM had anything to do with this, but GCC is showing no signs of slowing down.