Delighted to have you here!
Your smart will be 3 feet shorter than your Mini Cooper. You will like the standard features that you would normally find on Mercedes-Benz vehicles. After all these were designed by Mercedes-Benz engineers!
Like rfernatt and Putt-Putt's owner, I average 39-43 mpg depending on my lead foot.
This car is different to drive, but is very much like the nicest air-conditioned street legal Go-Kart that will still get you 40 + mpg depending on what you can coax out of it while having great fun. Also depending on how many other smarts are in your neighborhood, you will get lots of attention. And I do mean LOTS!

If you have not already, by all means go to
www.safeandsmart.com and
www.truthaboutsmart.co.uk, a website in the uk that is fun, interactive, and informative, though talks about the diesel version that we did not get. Another site that has a wealth of current information but also has information about variations no longer made is
www.evilution.co.uk . Our USA smarts are different as are Canadian smarts so not all information will apply.
Rich