Unless the power assistance system is on the way out or the damper is silly stiff you won't notice any difference at the wheel. Force you feel at the wheel is set by the internal torsion bar in the box connecting the steering column and worm. The bar twists when you turn the steering to open the appropriate spool valve to provide hydraulic assistance. Spool valve opening is proportionate to torsion bar twist. For all practical purposes the power steering system keeps the force at the wheel constant. If the actual load on the other end is greater then the bar will twist a smidgin more which theoretically means a bit more turn on the steering wheel but good luck with detecting that.
Steering damper is provided to control movement when loads on the steering change suddenly. Like one wheel on nice dry pavement and one falling into loose sand. Limits the rate of movement whilst the torsion bar twist and internal damping in the hydraulic system sort themselves out. Its dynamic, rate of change damping more than static force that is important. Bigger tube and more oil in the Terrafirma version just means it can work longer and harder without getting so warm that damping goes to pot.
Might matter to Baja or Paris Dakar types. But, as usual with most fashionable performance upgrades, the gains are where normal people never go. So long as basic build quality is up to scratch can't see any downside.
Clive