As far as riding in cars or on motorbikes, I prefer cars. The motorbikes are fun, do not get me wrong, but in a crowded city full of crazy drivers, I would rather be completely surrounded by metal and have a seatbelt.
Culturally speaking, a majority of Ticos do not have the extra money to put towards a car or to spend on gas, so they use the bus. It is actually really interesting as beggars and street vendors use this for business. It is common to see vendors standing in the busy street peddling yucca chips, Pipa fría (cold coconut water), and little trinkets or to have a person hop on the bus at one stop to sell little sweet cookies (roughly fifty cents) and then hop off at the next.