My wife's first tank on her new 2012 Jeep Compass 4x4 Sport, with 25% highway and 75% city, was 20.6 MPG. Thats with 89 octane, 10% ethanol. She has the CVT as well.
Ethanol gas will hurt you (10% or otherwise), although I understand how some states have 10% or more in every grade. Luckily out here in South Dakota, 89 octane is the only grade with 10% ethanol. 87 and 91 octanes are pure gas. In the 2001 Ram I used to have, I would get 1 to 2 MPG better without the 10% ethanol, and that was a big gas guzzling 5.9L V8. In the Dakota I have now, I get 2-3 MPG better if I do not use 10% ethanol. For that reason, and others, I do not use ethanol gas unless I absolutely have to. Have not owned the Compass long enough to tell you the different in MPGs with that, only reason it got 89 octane/10% this time is because the dealership filled it up for us as we were signing the paperwork.
2012 Jeep Compass Sport 4x4
2.4L I4, CVT II, Freedom Drive I
2010 Dodge Dakota Quad Cab 4x4
4.7L V8, 545RFE, Big Horn Edition