Answer
Equal
Work Step by Step
When the juggler throws a ball upward, he exerts an upward force on it. The ball exerts a reactive downward force on the juggler and the scale reading is higher than when he just holds the ball.
While the ball is in the air, the scale is reading less than when he holds the ball.
When a ball falls back into the juggler's hand, the ball exerts a downward force on the juggler and the scale reading is higher than when he just holds the ball.
Observing the center of mass of the system of the juggler + balls, taking $\mathrm{Y}_{\mathrm{c}\mathrm{m}}$ when all balls are in his hands as reference,
the center of mass slightly oscillates up and down about it as balls are thrown, flying and caught.
We can conclude that the extra forces cancel out over time, and that the average reading on the scale is the initial weight of the juggler with all three balls.
