I really enjoy 531 BBB, the baseline workouts are so straightforward, and the results have been extremely impressive for me personally. The only downside is I have outgrown my entire wardrobe, and it’s really difficult to find pants that will fit around my big ass and legs.
Regarding difficulty and injuries, just a reminder for everyone to read what Jim Wendler says about one rep max versus training max, and to start lighter than you think. If you are really crushing the plus sets you could consider upping your training max next cycle, but sub maximal is the idea. If the BBB sets are too easy at 40%, up them to 50 or 60%, or even FSL if you’re feeling really strong.