This is suitable for HD videos where the camera should take different position easily, but also pictures with telephoto.
The kneecap does not move a minimeter with D90 + Sigma 150-500mm + Grip MB80 or around 3kg.
Otherwise, good ergonomics, movement in all directions through the two axes of rotation.
The joystick is not very small but still fit in the upper pocket of my bag lowepro.
I really recommend this head, I use the Manfrotto tripod 055CXPRO4, also great.