Fans force air to flow in a rotational flow (due to the spinning fan).
It is easier to pull air through the linear radiator, then introduce the rotational flow with the fan.
Because of this, I cannot explain why some vehicles come from the factory with pushers.
I probably didn't explain that well, my apologies.
I dont think you will find many street driven cars that use pushers as the primary fan. The simply fact that the fan body is an impediment to air flow when the fan is off is a big neg. Now some cars do come with an elec pusher to augment a stock puller (often a mech puller). The pusher will be off in the corner of the coil, where it isnt overlapping the puller in terms of moving air across the coil.