Consumer Reports just looked at the diesel version of the Jetta, the TDI. They looked first at the gas mileage: was it any better? Yes. The regular gasoline version of the Jetta got 482 miles to the tank; the TDI went 665 miles before it needed a fill up. If you're looking just at fossil fuel consumption and CO2 emissions, the TDI is a clear winner.
But what about the problems with diesel fuels? They're notoriously dirty and smelly, aren't they? Testers agreed that the exhaust smells bad and acknowledges that current diesel blends put out more soot and causes more allergies, although the EPA says that's going to change. Other drawbacks to the TDI included slow acceleration and a noisy engine.
Thank you, Joel A., for the tip. [Source: WRAL]