I ride on a SS. Love it but as many says, it depend on the area you are. If there is a lot of hills, SS might not be the best choice. If you can have both, it it the best option. SS is great but when face with a head wind, it is not fun.
Might want to try to ride for a week in only one gear all the time (no cheating). If you see that you are confortable with it, go with the SS. That is how I knew that I was good to make the switch.