I have one, and will be putting one in a build I'm working on, as well. I've shot many different devices designed for a similar purpose, and have found the BFSIII to be the best option.
They don't like Ruger Uppers that are piston operation- I contacted the company and feel they were not up front with what they knew. never mentioned they don't like piston systems, I sent my lower in to get the factory install when an armor install failed to function properly, they told me it was for sure an install issue - sent my lower back to me after they did the install and the same thing happened when I shot it...problems...sent it back in along with the upper and they returned everything with a note saying their system was not compatible with my platform...Nice...their tech said I might want to put my Ruger lower on my Rock River upper....nice hillbilly fix, I wrote a letter to the owner and voiced my disappointment and all that this had cost me...not a word back from the company...totally unimpressed to say the least