Editor's note: This review was written in September 2011 about the 2012 BMW X5. Little of substance has changed with this year's model. To see what's new for 2013, click here, or check out a side-by-side comparison of the two model years.

Like an outstanding athlete saddled with an attitude problem, the 2012 BMW X5 has moments both of excellence and frustration.

You really want to love the SUV. But its driving flaws add up, and a decade of awful reliability stains any admiration. The X5 may appeal to some, but BMW has a lot to address in its next redesign, which may come as soon as the 2013 model year.

We tested an X5 xDrive35i, whose turbo six-cylinder slots below the xDrive50i's twin-turbo V-8. BMW also offers a turbo six-cylinder diesel in the xDrive35d. After a host of updates for 2011, the X5 changed little for 2012; compare the two here. Five seats and all-wheel drive are standard, and an optional third row brings seating capacity to seven.

We cover the 555-horsepower X5 M separately on Cars.com, but you can compare it with the regular X5 here.

Lagging Power

The X5's 300-hp gasoline six-cylinder eats up the passing lane, turning 50 mph into 75 mph with hardly a dent to its reserves. Its eight-speed automatic transmission delays a bit kicking down, but the drivetrain's abundant power across the rev range masks the lag, and a Sport mode holds lower gears longer, lessening the need for a downshift at all.

The problem is getting to all that power.

Accelerator lag spoils the X5's fun. Editors called the gas pedal hard to modulate, disconnected or just plain delayed. Throwing the transmission into Sport changes little. The light turns green, you step down, and the X5 xDrive35i … hesitates. It's maddening.

The 265-hp xDrive35d, which we last drove in 2009, runs short on steam at higher revs but starts off strong, thanks to less initial lag, a gutsy diesel engine and a more decisive transmission — with six gears instead of eight. We haven't driven the 400-hp xDrive50i, but BMW says its twin-turbo V-8 hauls you to 60 mph in 5.3 seconds. Those are Porsche Boxster numbers, but they'll mean little in everyday driving if the lag persists. If you drive the xDrive50i back-to-back with the others, click the link at the end of this review to email me your assessment.

Ride & Handling

Our test car had BMW's $3,500 Adaptive Drive option. It combines adaptive shocks with active stabilizer bars to minimize body roll, with a stiffer Sport mode — independent of the transmission's Sport mode — for more aggressive driving. As such, the X5 stays planted over broken pavement and fights midcorner lean. The brakes impress, with powerful, linear stopping power. Too much spirited driving, however, reveals limitations. Crank the X5 into a hard corner, even in Adaptive Drive's Sport mode, and the initial wallow and pushy nose reminds you it's no 3 Series.

The steering drives the point home: There's meager power assist at low speeds and numb feedback around town. A $1,550 Active Steering option varies the steering ratio for improved feedback and less effort. Active Steering has impressed us in other BMWs, and the X5 could well follow suit. But the standard setup disappoints, and the X5's yacht-like turning circle — 42 feet! — will have you cursing the low assist in close quarters.

It's hard to discern a difference in ride comfort between Adaptive Drive's Sport and regular modes. Either way, our X5 soaked up large bumps but fell into wavy up-and-down rhythms on uneven highway. Small imperfections peppered the cabin where our diesel X5, which had a fixed suspension, smothered them out. BMW offers standard and sport-tuned versions of the fixed suspension. Whichever you choose, save the money and skip the adaptive setup.

The Inside

BMW has yet to address the ill-fitting dash panels we noted in past X5 reviews, but the cabin feels rich otherwise, with low-gloss finishes, padding along your knees and elbows, and real wood and aluminum trim. Where the X3 gets cheap below eye level, the X5 stays consistent. BMW overhauled the earlier X5 navigation system's wretched iDrive controller for 2011. It's much easier to use, albeit still less intuitive than Mercedes' Comand controller.

My 6-foot frame had a couple of inches' rearward seat travel to spare, and headroom in our moonroof-equipped model was excellent. Ditto for the sightlines. Thanks to large windows and oversized side mirrors, the X5 hides little — and rams home the fact you can't see a damn thing out of its sibling X6 crossover.

Typical for BMW, the X5's base seats are firm, but contour-adjustable seats and bolstered sport seats, both with unique cushioning, are optional. The second row has good legroom and headroom, but the seat sits too low to the ground, resulting in raised knees. Despite myriad other amenities, it doesn't adjust, as the seats in some competitors do. The optional third row can suffice for kids; don't consign any adults to it.

Cargo room behind the second row totals 35.8 cubic feet; with both rows folded, the X5 has 75.2 cubic feet. Those figures beat the Audi Q7 and Porsche Cayenne, but the Home Depot crowd might favor BMW's Japanese competition. The Acura MDX and Lexus RX top out past 80 cubic feet.

Get the optional third row, and the resulting 23.2 cubic feet of cargo space behind it is generous — 8.2 cubic feet more than the MDX with its third row raised.

Safety, Features & Pricing

In crash tests by the Insurance Institute for Highway Safety, the X5 scored the top mark, Good, in front, side and rear impacts. The SUV hasn't undergone IIHS' roof-strength test. If you buy the optional third row, beware: The X5's curtain airbags don't cover it, as the curtains in the Q7 and MDX do. (Neither IIHS nor the National Highway Traffic Safety Administration evaluates third-row crash protection, so the X5 and other vehicles with the same oversight skate by.) Click here to see a full list of safety features.

Bad reliability has tarnished the X5 for a decade. Today's V-8 models rate average, but six-cylinders are poor. European luxury SUVs are a dubious bunch, but even among this mechanic-needy group, the X5 stinks, and BMW's four-year warranty is only par for the course.

The X5 starts at $47,200, in line with the Mercedes-Benz M-Class and Q7 but a bit pricier than the MDX. In typical BMW fashion, many features that are standard on the competition — heated front seats, leather upholstery, a moonroof — are optional. Shell out the cash, and the luxury options go sky-high — among them are a rear entertainment system, multiple parking cameras, quad-zone climate control, a third-row seat, a panoramic moonroof, ventilated front seats, heated second-row seats, a leather-lined dashboard and a massaging driver's seat. Check all the boxes, and a V-8 X5 can balloon to nearly $90,000.

X5 in the Market

A lot of shoppers still choose the X5 for its sharp styling, decent utility and an interior that lives up to BMW's luxury reputation. Through 12 years and two generations, it's been a runaway hit; only the redesigned 5 Series and venerable 3 Series outsell today's model.

But the X5 is slipping, confounded by problems large and small. BMW builds a lot of truly ­fun cars — and the first-generation X5, despite its size, fit the bill. I'd like to see the nameplate ascend there again.

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