I driven both and feel like a real world driver will get better MPG in a CVT. Period.
I regularly move my sisters (It is a CVT) and check the avg mpg and most of the time it's actually above 40...On a 500 mile trip with the car loaded up with crap, it got 36 going 75-80 mpg..with a head wind.
All and all though, I'd personally get the manual though because that CVT is the oddest transmission I've ever felt. lol.