 i3 is the most efficient in current market.  It is the lightest EV  (thanks to CFRP).  I can get 4mi/kWh easily.  Battery is 22kwh, but only drive able with 19Wh.  VW eGolf is nice, but you can't compare acceleration to an i3.  MB B Class is just too heavy and it does not have DC FC option.  In comfort mode, you can drive it as an ultimate driving machine.  In Eco Pro or Eco Pro +, you can drive it with efficiency.  You need to plan ahead for long trip.  I have 1300 miles in a month and total cost to charge is $25.  (There are some free charging stations).  There is no gasoline Tax.