Box Squat and Piriformis Mumbo Jumbo

Q: A lot of strength coaches and athletes (myself included) utilize variations of the box squat. I've heard other strength coaches (one in particular) indicate that it does not fully stimulate/activate the piriformis. What are your thoughts on the issue of the box vs. free squat in terms of advantages and disadvantages? I currently utilize both variations however it would be nice to be able to