I just drove to work in 25MPH winds, doing 60-70. You can definitely feel the car moving about but, as was pointed out, it really doesn't seem to lose track (at least at those speed winds). I felt it was akin to driving on a very snow-covered hard-packed road, where your car rides in the tracks in the snow. However, I don't have power steering, which IMO probably makes it easier... I never like the way power steering makes me feel like I'm not in control of the car.
Bottom line: the car's a cube. It's going to handle like a cube in the wind, just like a minivan. ::

:: It's sort of like complaining that there's no back seat. You saw it was a cube when you bought it.