The symmetrical two post car lift has arms of equal length, and the vehicle sits at the centre equidistant between the 2 arms on each side, and the weight is distributed evenly across the 2 post lifting arms.
The asymmetric 2 post car lift has one arm on each side of the lift slightly longer than the other, and this allows you to position the vehicle slightly further back on the 2 post car lift, meaning that most of the vehicle weight is taken on the rear arm on each side of the car lift, the benefit being that it makes it easier to open the doors to access the interior, without impacting the column on that side of the car.