Am I reading this right? He says he is comparing clang 3.8, which is a month old, to gcc 4.8, which branched over 3 years ago. I would rather see what gcc 6 does with this. That release should happen in a month or so.
Regardless, I think the author's conclusion is overly specific and really should have just been "trying all of the various tools for doing something is useful even if they're theoretically comparable".
As others said, it makes sense for everyone to try different toolchains and see what works. It is possible to test newer gcc versions by installing in /opt or something, just make sure to get the right libstdc++ at runtime. With ABI changes, updating the distro gcc is too much trouble.