During the manufacturing process, plywood veneers are randomly selected and stacked up into panels. You may get 4 veneers of earlywood stacked above 1 veneer of latewood. Most plywood panels are overbuilt to cover the statistical range that guarantees each sheet of plywood meets the minimum standard. However, osb feels stiffer when you walk across a floor covered with it because there are no occasional weak panels like plywood. Smaller trees can be used to make osb.
Wood fiber is used more efficiently in osb.
Osb is stronger than plywood in shear. Shear values, through its thickness, are about 2 times greater than plywood. This is one of the reasons osb is used for webs of wooden I-joists. However, nail-holding ability controls performance in shear wall applications. So both products perform equally well as shear-wall components.