Made two trips of about 230 miles RT each between Anderson SC area and Columbia SC area. Same start and end points both times. On first about 80% interstate, 15% two lane country and 5% city. Got 28 MPG driving about 5 over speed limit. 2nd was about 60% interstate, 35% two lane secondary and 5% city. 28 MPG again.
Not great, but not bad either.

 

I usually only get 21 MPG. 28 MPG is very good for you.

 

I went NY- Florida -NY. Average 24.5MPG. Speed was from 70 to 90. No cruise control. The car is 4Matic. Funny, but my Diesel GL (the huge behemoth) easily beats E-class and gets about 26-28MPG on a freeway.

 

Poor Gassers...I get that in mostly city. 40 mpg mostly hwy.