Which gets hit harder?
I do not think your question makes sense? Maybe rephrase it?
Are you saying bullet spin vs downspin?
but bullet spin tends to be straight as an arrow and hammered by better hitters. once she fully adjusts and and her speed matches her bullet spin you'll be happy for the downward bite on the ball.
Bullet spin only moves with gravity and will most definitely get hit more often and much harder. It's easier to square up on a ball that's not breaking.