The smart is definitely fun to drive, and has excellent mileage. My best tank so far, driving conservatively on the highway, has been 53 MPG. Realistically one should expect high 30s to mid 40 MPGs, depending on driving. Mileage suffers above 65 MPH as the drag increases. The quirky transmission is the car's greatest weak spot. It is neither as smooth as a traditional auto, nor as quick to change gears as a manual. It literally takes a certain learning curve to get used to it and get smoother. Nevertheless, the car is super fun to drive. If you don't want to wait a full year for a reservation, get on your local dealer's "orphan" list for cars that have been turned down.
Fun to drive and great mileage.
The transmission is quirky and the brakes a bit touchy at low speeds.