How can something this big and heavy drive so smoothly? That’s what I’m wondering after spending a short weekend roadtrip in a 2013 Mercedes-Benz GL350 Bluetec. Bumps and other road imperfections I know exist barely affect the GL350 in Comfort mode.

As we escaped Los Angeles and made our way toward a nearby coastal city about 50 miles away, I began to appreciate how quiet the big SUV is, too. You do hear the GL’s diesel six-cylinder engine, but it’s not overly intrusive. I spent a few weeks driving Motor Trend‘s long-gone Infiniti QX56 that had a 400-hp V-8, and of course, with that vehicle in mind, the GL350 left me wanting more power. Realistically, though, how quick should gigantic premium SUVs really be? For those who aren’t interested in the GL350′s driving range and efficiency, the 2013 Motor Trend Sport/Utility of the Year is also offered in gas-engined GL450, GL550, and even GL63 AMG variants.

On the road, my front passenger and I enjoyed the massaging seats, though I began to wish the central dash navigation screen was much bigger and the speedometer could switch places with the tachometer. When the GL goes in for a refresh, I hope Mercedes can find the space to include one of the S-Class’ 12.3-inch screens. I used the adaptive cruise control almost the entire way down to our beach-side destination. Like other such systems, Mercedes’ technology allows you to adjust the following distance, and although the vehicle was a little aggressive braking and accelerating in slower traffic, it really helps make roadtrips more relaxing.

If I were considering huge luxury SUVs and didn’t know that loaded minivans would be a better choice for those who need to move people and stuff, and want lots of features, I would definitely consider the GL350 diesel as well as the gas-powered GL450, QX56, and the upcoming Cadillac Escalade, among others. Though I did spend extra time fighting for a diesel pump than I would have to refuel gas-powered GL variants, the GL350′s efficiency advantage -- 19/26 mpg city/highway versus 14/19 mpg for the GL450 -- is simply too great to keep off automotive shopping lists.

Photos show a 2013 Mercedes-Benz GL350 Bluetec with standard 19-inch wheels; our test car wore optional 20-inch alloys.