For several years I took a bus home from school and then work. I would car pool in to school/work most days and need a ride home.
Why? I and my wife at the time had only one car for both of us. As students we didn't have enough money to have a second car and the cost of parking at the university was astronomical. When I graduated and started work, I just kept that up.
However, I hated it. Busses here come once an hour and only from 7 am to 6 pm. The busses also run +-15 minutes from their schedule. Thus you had to be there 15 minutes early and you very easilly could stand there until 15 minutes late waiting for the bus. Add to that the 15 minutes it takes to walk to the bus stop and another 15 mintues from the bus stop. Total time wasted: 1 hour, double that if you need to take it both ways. And if you miss the bus, prepare to stand around another hour. Also if you miss the last bus, prepare to walk home.
So, as for your poll options: I formerly used it regularly, but I don't use it now (divorced and have my own car). When I did use it, I used it because the bus was far cheaper than car payment + gas + insurance + parking + maintenance + car depreciation (most people forget all those other costs and only consider gas in the equation). I don't use it now because it is far too infrequent and inefficient.