A small engined scooter may well return over 90 miles to the gallon, whereas even a small car could only really achieve maybe 40 to 60.
Insurance would be hugely different, tax would be a marginal difference given that small diesel cars can now qualify for road tax of £35 !
I never paid to have anything done on my scooter as they are pretty simple to service.
I was never too worried about falling off my bike, I was most worried about being run over when I did fall off .....