Just to let you know - I have been using this compiler to port a rather complicated C++14 project and it seems to work nicely. There current issues are filed at https://github.com/rinigus/pkg-gcc/issues .

We are also missing README and example projects to show how can it be used.

All in all, I would suggest to try to use it and everyone is welcome to chip in by fixing the problems with gcc packaging at OBS.