I own a (2013) Ford Fusion hybrid, which has exact same drivetrain as the C max, and same mileage ratings.
What I'm going to say will 'fly in the face' of a lot of whats been said, reported here, but here goes:
First off, the 47 mpg most certainly IS realistic and very attainable. I get that or better pretty regularly, in driving the Fusion to work and back every day (26 miles, 'bout 80% interstate).
The secret is in how you drive it. Its like any other car - if you drive foot-to-the-floor all the time, have to be the first away from every traffic light, and the last one to start braking to stop, yep, your mileage will be in the toilet. Folks reporting 35 mpg, I'm betting were driving it like that.
However, if you drive more sensibly, and learn how to drive the hybrid right (keep it in EV mode as much as possible), you will easily average 47 mpg or better. I've seen as high as 50 mpg on a few trips.
Second, I find the JD Power Ranks article a little surprising. Contrary to what that article suggests, our hybrid Fusion has been absolutely flawless, and a blast to drive. Perhaps the defects they had are specifc to the all new C max, not the Fusion, I don't know. I do know we have not had one bit of trouble out of our Fusion so far. And, it gets driven a lot - its my daily driver to work and back, and we tow it with us, use it on all our camping trips (4 trips so far this season).
As far as towing goes: Really, the simplicity and ease of towing this vehicle 4 down behind our MH is the main reason we bought it. The fuel mileage was only an added bonus. LOVE how simple and easy 4 down towing is with it - just put it in neutral and go. No crazy procedures to go through, don't have to start and run engine every few hours, none of that junk. As already said, you definitely have to run a charge line to the battery, but thats a very, very minor thing to add (I did it myself easily), and is a good idea, regardless. Also, its a great vehicle to have at a campground - its like driving a big golf cart, since it runs on electric power when traveling at slow speeds through campgrounds. Gas engine doesnt even come on until you get up to higher speeds. That, and its just really cool in general, driving a vehicle that uses ZERO fuel when stopped at stoplights or whatever, and at lower speeds. I can typically get completely out of our neighborhood and onto a major road, before gas engine even comes on.
Anyway, you can count me as one 'yay' vote, in favor of the Fusion Hybrid. Not sure about the C max, but the Fusion is definitely a great choice for a 'towed' vehicle.