Like a lot of systems folks I use sed, a lot. It is probably an unhealthy amount of sed use but so be it. I operate on a lot of Linux servers but my desktop environment of choice is Mac OS X which means BSD tools (not the Linux-y GNU tools).
The differences are relatively subtle between BSD sed and GNU sed. However, most of my work is done through iTerm (a literal black box). I frequently find myself diving down rabbit holes and I really do not want to have to remember the differences between BSD and GNU sed. I want the same sed everywhere so I compile GNU sed on Mac OS X:
Disable Mac OS X System Integrity Protection (aka rootless). This is a new-ish step thanks to Mac OS X El Capitan