The Infiniti QX56 is a large luxury SUV that is based on the Nissan Patrol which is sold in markets outside of the United States and is quite popular especially when configured with a powerful, efficient diesel engine.
The QX56 is not available with a diesel power plant but it does have a large 5.6L V8 that puts out some impressive power. Output is 400 HP and 413 pound feet of torque and the engine is paired with a 7 speed automatic that helps the vehicle make the most efficient use of all that power. The EPA rates the QX56 at 14 miles per gallon in urban driving and 20 miles per gallon when driven on the highway.
You can get this Infiniti in either a four wheel drive or two wheel drive configuration but if you are serious about having an SUV that is capable of managing slippery weather or off road driving the 4WD is the only serious choice. The two wheel drive model might be okay if you will be only pavement and easy gravel or dirt roads all the time. It would not be a good idea for any part of the country where it snows given the size and power of this SUV.
If you are concerned about handling and the effect that the 4WD system will have on it you might like to know that most of the time the QX56 is driven by the rear wheels however when the automatic four wheel drive system detects poor traction it will shift power around to distribute it to the wheels that can put it to use. If you plan to tow with your QX56 you should be set and ready to go since it features a tow rating of 9,100 pounds.
The styling of the QX56 has always been a bit different and it might strike you as being too brash or loud but that is actually fairly common in this segment if you look at other models like the Cadillac Escalade which is famous for being modified in fantastic, overdone ways by many owners. Probably some of the most refined and conservative styling in this segment is found on Land Rover models and you might want to consider the LR4 if you want a SUV with plenty of passenger space, excellent off road credentials and more traditional styling.
If you would like better fuel economy than you can get in the QX56 then your best options would be the Audi Q7 TDI and Mercedes GL350 BlueTec which both use diesel engines to achieve MPG performance in the range of 25 MPG when on the highway. Their horsepower output is down compared to the gas V8 in the QX56 but torque numbers are generally impressive in turbo diesel engines and both the Q7 and GL350 match the Infiniti in that area.