I'm not entirely sure. My wife's Versa is automatic

so it's really not a fair comparison.
I do knoe that my wife's car consequently does have worse mileage than my FiT and thus much less than my cube, but I have Manual Transmission, and drive it gently, so I tend to maximise my fuel economy more than average.
I think it may have to do with weight vs. size and thus how much the engine needs to labor when in periods of accelleration. oh and my wife does not drive like me, so she would push it more.
Someone who is more familliar with physics than myself may be able to know whether or not the Versa tends to face a lot of drag or not, due to it's height and such factors. Perhaps the cube works out better this way because it might be low-drag in comparrison. I don't knoe though.