I did BBS for a bit over four months and noticed a great improvement in strength as far as The Big Five went but I realised I wasn't using a lot of minor muscle groups. I bought YAYOG and think it will suit me when I am fit enough to get on the bottom rung. I am 62 and had really not done any exercise apart from walking for over 20 years. I test myself every now and again and know I am improving but I understand it will be a long haul, although well worth the effort in the long run. Having said that, I think PBF is fine for anybody who wants best results for minimum time taken and effort put in.
Why use a sledge hammer to crack a nut when a steam roller is even more effective, and, is fun to drive.