Approximately a year and a half ago my brother did an evaluation of the Effin' A "Adjustable and Stackable" compensator. He liked it so much he kept it, and has continued to put rounds through it since. The adjustment screws that effectively "tune" the compensator have remained where they are supposed to be and have not, so far as I am aware, caused any issues or failed. Although he tends to treat his weapons like a classic car (vs. my tendency to treat them like a lawnmower) I am confident that the amount of use and abuse the Effin' A MKI has endured would have caused an issue if there were any real likelihood of one occurring.
Ares Armor has now redesigned the Effin-A Compensator. The MKII model, which weighs approximately half of its predecessor (2.5oz.) and is a one piece design. It features a 21-port "minimalist tuning system" as opposed to the 28 ports of the MKI, with set screws that will bottom our for a secure fit and clear chamber.
One question that repeatedly comes up is that of the Effin-A's flash mitigation (if any). To be candid, I have not watched the MKI during any night fire since the .308 version came out; I will attempt to get some images or video next time we go out to address this.
The Effin-A MKII is currently available only in black and for 5.56mm/.223. I will advise when and if they expand that lineup. They are listed on the Predator Armament page for $89.99.