I had a scooter last year, and the city I live in is completely flat...I couldn't imagine using one in San Francisco! But I got rid of it after I had an accident; went to make a turn in wet conditions, slipped, and the scooter fell on and broke my right leg. That was the end of it; got a car instead. But that accident aside, the problems with scooters are:
-No extra space for storage.
-Sucks in anything but sunny, dry weather.
-Forget about using it during the winter if you have snow
Basically it's just like a bicycle, and hell if you aren't going to far, just use a bicycle instead. It's cheaper, too. I got myself a nice folding bicycle, so it's easy to store and I can even take it on busses or trains if I wanted to.
I wouldn't have been able to use the scooter all year round due to the large amounts of snow we get here, and also having no storage space sucked...forget about the grocery store or any other store where you might end up buying large amounts of items or simply a large item. Forget about the highway, too. Since you're pretty much restricted to the city or town you live in, the scooter is nothing more than a bicycle for lazy and old people. Probably explains why I see no one but the elderly using them.
