Yep, I'm doing the Big Beyond Belief Serious Growth 3 right now and have been for a while. I am finishing up week 3 of the first phase this week and then next week is the de-load phase for 3 weeks. I am doing the six day per week one workout a day routine and like it alot. I like that the rest periods and reps ranges are mixed up over the course of the week which has been great for my joints.
Muscle size seems to have improved- I lool a little harder too but that could be wishful thinking on my part. The bottom line is that I feel it is effective and worth trying. I recommend it to everyone who asks me about working out.