In the January 2014 issue of Consumer Reports, the Mercedes-Benz GLK350 is recommended. It received a road test score of 77. It has a 302 hp 3.5L V6 engine.
It is mentioned that if you want to go with a more fuel-efficient model, aim for the GLK250 BlueTec model with a twin-turbo inline-four cylinder diesel engine.
Both models of this SUV have the same towing capacity of 3,500 lbs. The GLK250 has nearly 100 lb*ft more torque, and 102 less horsepower.
Here is the link on Mercedes' website for this SUV: