I have had the car for a week now, and I drove ot to Seattle WA last weekend with my son. It is a very nice smooth touring car, with great seats, very low cabin noise at speed, comfortable suspension and good taut handling. We got a few inquisitive looks down there, from people who had not seen one before.
On the ride down to Seattle on I-5, with a couple of stops, we averaged 6.2 L/100 km (38 US MPG), driving at 115-120 km/h (72-75 MPH), and not using cruise control because the engine was green and needed to be broken in with varying engine speeds. On lower speed highways, somewhat over 40 US MPG would be easily achievable, say cruising at 55-60 MPH. This is normal driving, mod cons on, two up with four snow tires on rims and luggage inside the car, no attempt being made to drive economically.
So the consumption is pretty good for a car of this weight (nearly 2800 lbs unladen - cargo / driver+passenger capacity is 1366 lbs on top of that), with wide 205 section 16 inch tires at normal pressure, 136 HP and decent acceleration....
My lifetime average so far is ~32 US MPG, and that includes the first tank which the dealer had filled on delivery, which we burned 3.5 hours of idling at the US border, first getting into the country, and second, getting back into Canada! I hope to get the lifetime figure up to 34+ US MPG, and I should be there soon.
Premium, 92 octane, which is cheaper than the Shell Ultra Diesel I use in the smart!
The car has been in our possession for close to 4 weeks now....I have it running on 4 snow tires, which is harming the fuel economy a bit, though 7.5 L/100 km overall is not half bad. I doubt we'll be hitting 34 US MPG overall all that soon, though it could happen by next spring. On www.spritmonitor.de, our car is already the most economical B-Class with the two litre gasoline engine!
The car's on-board fuel consumption computer seems to be about 4 or 5% optimistic, but it's a useful driving aid.
It is a great touring car and very comfortable. We are very glad we got it.
Update: on gummy winter tires it's still averaging about 7.6 L/100 km in mixed use. When I put the summer tires + alloy wheels back on in March, it should get down into the lower 7.x range. For a large car, that's pretty decent. I don't make any special effort to drive economically, other than usually sticking to speed limits (though I wound her up to 160 km/h last weekend).
the on board computer is very optimistic about fuel consumption though. It's about 5-7% too optimistic.....
The FE icon in my signature is about to go to 7.5 L/100 km (metric version) as the consumption continues to fall. Now I'm back on all-season tires at normal pressures.
I am not driving it unusually gently. Maybe I'll get the lifetime average to 32 US MPG later this year. We'll see. It is pretty decent, for a large and relatively heavy car, that usually has three or more people in it when it's being used.