Review of the BMW X5 and Mercedes-Benz ML350, plus Volvo XC90

Helped by an impressively quiet and luxurious cabin, the redesigned Mercedes-Benz ML350 beat the sportier, updated BMW X5 in a match between two German luxury SUVs.

The new ML jumped seven points in our Ratings, with an overall road-test score of 76, because it's more fuel efficient, quicker, and quieter than the previous model. The transmission and controls are also improved, although this ML doesn't handle as well.

With a turbocharged six-cylinder base engine that's quicker and more fuel-efficient than the previous one, the X5 gained two points to earn a 69. But its choppy ride and overly heavy steering did not improve. Also heavy is the X5's price of $62,675, almost $6,000 more than our comparably equipped ML's $56,960.

Both vehicles rank midpack in this category, below the less expensive Acura MDX ($46,715) and Lexus RX 350 ($47,381). Although they scored well enough in our tests, neither model is recommended because the ML350 is too new for us to have reliability data and the turbo X5 has had below-average reliability.

We also tested the Volvo XC90, which was lightly freshened for 2013.

We tested the ML350 and X5 SUVs with their popular six-cylinder gasoline drivetrains, although diesel and eight-cylinder engines are available for each. The ML's 302-hp, 3.5-liter  V6 is mated to a seven-speed automatic transmission, and the X5's 300-hp, 3.0-liter turbo six is mated to an eight-speed automatic. They provide smooth, powerful acceleration and delivered 18 mpg overall on premium gas, three less than the Lexus RX 350's 21 mpg. The ML350 can tow an impressive 7,200 pounds, topping the BMW's 6,000-pound limit.

In everyday driving, these SUVs exhibited good handling, with little body lean. The ML's steering is responsive but a touch vague. The more agile X5 holds the edge in handling and steering, but its steering feels heavy in low-speed situations such as when parking. At its handling limits, the X5 was capable and controlled; the ML350 was considerably less capable, with lower limits.

The trade-off for the X5's sportiness is a stiff and choppy ride that's particularly annoying at low speeds. Here, the ML350 wins with a more supple, composed ride. And although each vehicle has a quiet cabin, the ML350's is exceptionally so.

Both cabins are very posh. Drivers of all sizes will find plenty of room and a good range of power-seat and steering-wheel adjustments in either the ML350 or the X5. And their second-row seats are comfortable and roomy enough for three.

We bought our X5 with an optional third-row seat, which is suitable only for small children. The ML doesn't offer a third row; the larger Mercedes-Benz GL has one, but it costs about $4,000 more.

Controls are complicated in these vehicles, but the ML350 has more direct radio hard keys and simpler menus than the X5's iDrive. Each has straightforward climate controls and an awkward electronic shifter.

The X5's optional third-row seat takes up most of the cargo space when the seatback is up. With it folded, the BMW's cargo area is slightly smaller than the ML's roomy hold. Cargo space in both can be extended by folding the split rear seatbacks.

The Volvo XC90 has been updated, but its design dates back to 2003 and isn't competitive among today's luxury SUVs. Its reliability has been below average and, with a test score of 58, it scored too low to be recommended.

A 240-hp, 3.2-liter six-cylinder is the only available engine. A more powerful V8 was discontinued. Matched with a six-speed automatic transmission, the XC90 delivers slower acceleration and worse fuel mileage than more powerful competitors. We recorded a middling 17 mpg overall on regular fuel with our all-wheel-drive model.

Pronounced body lean and relatively slow steering make the XC90 more ungainly in normal driving than competing European models, but steering is well weighted, with decent feedback. The ride is stiff and busy, but it settles down at highway speeds. At the track, the Volvo reached its cornering limits early, but stability control helped keep it on course.

The XC90's interior is spacious, versatile, and well finished, with comfortable seats all around and a high seating position and good visibility for the driver. The third-row seat is suitable only for kids. Climate controls are simple, but the radio is not intuitive. The outdated navigation system can't be programmed by voice. It shares a pop-up screen with a backup camera, but it takes 10 seconds for the rear-view screen (shown) to rise and show an image after you shift into reverse, too slowly to be effective as a backup aid. By that time, you could be done backing up.

Its cargo area is roomy, and a flat floor makes loading easy.