I got up close and personal with the Wii Wheel at last week's Nintendo Media Summit, where I (literally) played hours of Mario Kart Wii. I tried playing with the wheel attached and without, trying different configurations of play. And after spending a day with the peripheral, I can't exactly call it great, but it's not horrible either.
My first thought when this was announced last year was that I didn't need a piece of plastic to hold my Wiimote in place; I'd steer the controller by itself just fine. But last Thursday came around, and I approached the wheel cautiously, got comfortable, and even warmed up to the little white circle. While the game can certainly be played without the wheel, there's something that just feels right about holding it in your hands. There's more room to grip with your hands, and you're given a better frame of reference as to how much you're steering.
There is also an elongated, horizontal button on the back that acts as a mechanical proxy for the B trigger button on the underside of the Wiimote. Hitting the B button is a key part of the drift element in Mario Kart. Without the wheel, trying to hold the Wiimote horizontally in two hands while pressing the 2 button for gas and the B button for drift was a bit awkward. Not so much with the wheel in the hand.
However, the wheel took a little getting used to. I found myself oversteering at first, forgetting to steer later, and waving the wheel in strange directions (also exhibited in the above video by Kotaku's Michael McWhertor). But after awhile, I calmed down and found a sweet spot where I could play with a bit of skill. So the Wii Wheel may not be God's gift to racing control, but it doesn't make the experience any worse either. And as far as Mario Kart itself goes...go talk to Kotaku, they're the game freaks. [Mario Kart Wii @ Kotaku]