With three rows of seats and some off-road pretensions, the GL is the tallest and heaviest of the three.
The GL wraps you in the expected Mercedes luxury along with the expected annoying Mercedes quirks ("Hey, my back-up camera isn't working. Oh, of course... I forgot to turn on the radio!").
Third row seating isn't bad but it's nicer in other similar-sized SUVs such as the far-cheaper and more beautiful Buick Enclave and Mercedes' own R-class crossover, which is essentially a longer and lower GL.
Like the Grand Cherokee, the GL320 feels like it's towing a trailer full of boulders at low speeds. The six cylinders burble at low RPMs as the GL rumbles out from a stop.
Once again, though, punch the gas and the GL takes off in a surprising burst of speed.
Mercedes' sophisticated magnetically-adjustable suspension system, which can be switched from "sport" to "comfort" manually or automatically in response to driving style, keeps the big GL rolling gently over city bumps or reasonably stable at higher speeds.
EPA-estimated fuel economy is 20 miles per gallon overall, compared with 15 in a V-8-powered GL.