Squat Technique

What are the benefits and risks of the powerlifting squat versus the olympic squat?
What do you think of devices like the manta ray, top squat and safety squat bar?

I hav a manta ray, and i use it as the guys at westside do, as a slightly harder alternative form of squat where the bar posision makes the squat harder by a little. (higher than high bar squat)

I also would like to know about draper’s “top squat” look sgood for my elbows and wrists which can get sore from squatting alot.

anybody tried this before?