I thought both of these were worthy contenders, but I would only have voted for one of them.
The Volt is a solid piece of technology, but it isn't revolutionary--under the skin, its architecture is not all that unique from a Prius or a Fusion Hybrid. Despite what GM says, the Volt is in fact a plug-in hybrid, and it can even (under some conditions) send gasoline torque to the wheels. Like the other hybrids, it has a gasoline engine connected to a generator and traction motor through a planetary gear set. It has been tuned in software not to behave like a gasoline/electric hybrid. As neat as the Volt is, it is not quite the revolution that an all-electric car would be.
For the COTY I would have voted for the Hyundai Sonata. Here is a company which came from a legacy of pushing boring, cheapy cars using a long warranty and low prices. All of a sudden, they are building world class cars, with high quality and handsome design. And unlike the Leaf and Volt, the Sonata will sell in high volumes. Considering its market impact, the Sonata should have won.
For TOTY, I agree with the panel, and I would also have picked the Explorer. A uni-body, front wheel drive mid-size SUV is the way of the future. Most SUV owners don't need to go offroading, and don't tow anything either. Most of them really just want to sit high and look stylish.
The Chrysler trucks were strong contenders, and I actually thought one of them would win, as a pat on the back to Chrysler for not dying. The Grand Cherokee appears to be a solid product and much improved compared to the junky stuff Chrysler was selling previously.