Which alternative will be more efficient and beneficial for Bathroom Ventilation? How?
Moist hot air rises.  If you have a fan placed near your shower on the ceiling that can move a lot of air out you will have little to no condensation.  Fan should be turned on when you get in the shower and generally speaking should stay on twice as long as the shower taken.  If you buy a fan sized for a bathroom 2 times your size and keep your bathroom door or window open while showering (if you can) you would more than do it.