My civic hybrid gets better mileage than the current smart cars. However the ones in testing will be better. The advantage of being able to park almost anywhere is nice, but I prefer the styling and size of my civic (which is not huge, but big enough to take whatever I need and strap my bike to the back when I can't use it to get where I need to be
The smart car is a step in the right direction, but fuel cell technology holds more promise for the future. We just need to build an infrastructure system to support it.