Minis are very popular, but NOT because of their reliability or low cost of ownership. You can read any reliability study / survey of recent years and the mini is always in the bottom somewhere. The Mazda is leaps and bounds better. At 27 mpg on regular, you can drive the wheels off that Miata and still come out ahead. Nothing uses that much less gas where you will ever justify buying another vehicle.
Now if you are jonesing for another car, come out and say so, but don't bring up gas mileage.
G