Great post by "Willald" in answering the questions from the OP. While I have the previous version of Ford's hybrid technology, I couldn't be happier with my 2012 Fusion Hybrid. As far as I'm concerned, this car is the best vehicle I've ever owned. The only cars that come close were the Lincolns that I leased 20 years ago when I worked for Ford. And of course those Lincolns couldn't come close to matching the fuel econommy of the Fusion hybrid - - but they were wonderful road cars.
As has been mentioned, whether one achieves the rated fuel economy depends greatly on driving habits. I'm a rather conservative driver and have not had any problems achieving the EPA ratings on my Fusion. In fact, after 14,000+ miles, my overall MPG is pretty much right on the combined EPA figure of 39 MPG.
To achieve good highway fuel economy I never exceed 68 MPH. Fuel economy drops off noticeably if you exceed that speed, even by only 2 MPH (that may not be the case with the 2013 model). Another thing to keep in mind is that colder temperatures impact hybrids more than regular gas powered vehicles. Since a hybrid is most efficient when running in EV mode, colder temps require the gas engine to take longer to reach normal opperating temperature before it can shut down and the vehicle go into EV mode. For that reason, shorter trips made in the winter time will very much negatively impact fuel economy.