Well took delivery yesterday and did 157 miles of driving today, a 100+ mi loop to a family event, and then another smaller loop. Probably 75% off highway driving, backroads, moderate hills, 30-55mph speed limits. Then some highway driving for 25 miles or so, some in 75 mph zones, setting the cruise control at 77mph. And a couple "play with the paddle shifters" floored pedal highway entrance ramp launches, and one "old person" power pass. A bit of really slow city-esque stop and go driving where I saw the mpg really drop.
Overall, the entire day of driving, the MFI reported 35.1 mpg average. Did a reset on the calc in another screen after the city type driving, last 110 mi saw 35.6 mpg. I was impressed. Lightly loaded car yes, but overall pretty efficient. I found that the C300 has a regenerative braking system (also to pull down speed going down hill under cruise control without down shifting) and one of the MFI screens show you your "bonus" miles under regenerative braking, I think it said bonus 49 miles.
A real joy to drive this one, even though our 2018 Jeep Grand Cherokee is nothing to sneeze at either. Will be interesting to see what kind of MPG averages we get in long haul road trips this coming winter with a pretty fully loaded car. Most impressed, even on the test drive last week, was the steering response. I bet the lock to lock steering is small, it darts as steered when needed with almost no existent body roll, and we pushed it on off ramps 10-20mph more than what would normally feel "comfortable" and it tracked like it was on rails.
