the platinum has lumbar, side bolster, thigh and neck adjustment for the driver seat. the passenger seat has lumbar, side bolster and neck adjustment minus the thigh. I'm sure the luxury or premium would have the similar adjustment albeit not as detailed as the platinum to help with seat comfort.
After 8 yrs in 3 MB GL's ...believe me, the escalade seats and leather quality are distinctly an improvement! Enough of a "firmness" to satisfy the Euro market, BUT not as hard as the WV Touareg or the MB GL.