For buyers looking for a fuel efficient car, diesels provide an alternative to hybrids. Popular in Europe for years, more diesels are making their way to the U.S. market.

Modern diesels escape many of the liabilities of earlier designs. They are quieter, burn cleaner, and have much improved acceleration. Fuel economy is considerably improved over gasoline-powered versions.

But buying a diesel usually means paying more up front. Finding a diesel pump isn't quite as easy as locating gasoline, and diesel fuel prices recently have fluctuated widely. Except for Volkswagen, diesel vehicle availability is also limited to high-price luxury brands.

In this video, we take a look at four diesels—Mercedes-Benz GL320 Bluetec, BMW 335d, BMW X5, and the Volkswagen Jetta TDI—and their pros and cons.

—Tom Mutchler