GKN will last forever because they are made from nice hard metal
sometimes however cheap ones are better for offroad becuase they are less likely to crack the bell through shock, becuase they are not generally as hard
however, they can/tend to snap the shaft under heavy torque conditions
in short, cheap ones will probably be ok
they wont manage 150k like GKN but then they do have other qualities being softer, plus they are much cheaper which means you can fit new units with new splines more often rather than running old worn spline units for longer
i bought a pair of 2522s from bearmach as a temporary measure before i fitted the ashcroft units and they seemed to be most satisfactory in quality so would have been happy to use them in any other situation
cheers