The Mariner Hybrid—along with its corporate sisters, the Ford Escape Hybrid and Mazda Tribute Hybrid—is the most fuel-efficient SUV on the road. Elegantly cast, it has a 2.3-liter four-cylinder gasoline engine that teams with an electric motor/generator to deliver strong acceleration that beats a V6-powered model but with excellent fuel economy (34 mpg city/30 highway). Software revisions to the hybrid control system help make the transition between electric and gasoline power seamless. A CVT (continuously variable transmission) is smooth and powerful. We also liked the new power-steering system for what it adds to the vehicle’s car-like ride and handling. Side-curtain airbags and stability control are standard, with all-wheel drive available as an option.