I got about 1300 miles with mine. Lots of hills though on my trips I took.It seems the free supercharging miles were converted to kWh at a rate of 5 miles = 2 kWh; by this math, it amounted to about 400 kWh of free supercharging. Since I am generally using about 250 Wh per mile, I would get about 1,600 actual miles.
As the disclaimer goes, your mileage may vary.