A solid, SOLID addition to the core rules for FIST. I like the use of GLOG light source die (I think?) to track the 'trip quality' of drug test participants.
Even if you don't want to shift to 60s spy fiction from FIST's 80/90 late Cold War vibe, or play a "Phantom Doctrine" type campaign, BRKN is worth having for coming up with new CYCLOPS CRO teams if nothing else.