I just turned 1000 miles this morning and have no problems to report.
I've checked the MPG three times. The first check was 41mpg during the first week and driving at lower speeds in the city. The second check was 38mpg driving combined city/highway at higher speeds up to 70mph. The third check this morning was 37mpg driving combined city/highway with speeds up to 75-80mph with passenger. All driving was in the Auto mode with the A/C on.
This car is what it is, an economy car, with slower acceleration and a rougher ride but with that said I still enjoy the Smart and very happy with it.