Midsize sedans blend so seamlessly into the American automotive landscape that you may never really notice them. They're pragmatic transportation vessels that competently and anonymously troll freeways and mall parking lots. These high-quality sedans provide roominess, comfort, efficiency and plenty of luxury features — all at an affordable price.

So it's no surprise that in 2009, midsize sedans were the single largest volume segment, with nearly 20 percent of the market. Accordingly, this segment is a critical battleground, with many new sedans hustling to catch our attention. We knew it was time to see if the newcomers could match the perennial top sellers.

We started with the segment's three most popular cars — the Nissan Altima, Toyota Camry and Honda Accord — and drove them alongside five challengers: the Mazda6, Ford Fusion, Suzuki Kizashi, Chevy Malibu and Subaru Legacy. We ran them through our tests, a day of hard driving in the hills near Los Angeles and a 360-mile fuel-economy loop.

Since four-cylinder engines and automatic transmissions make up the majority of the sales in this class, we ordered each car that way. Instead of ranking these very similar vehicles in a finishing order, we decided to call out the combination of each car's strengths and represent them as icons. So, here are eight of the top four-door sedans in America — and what they do best.

Testing Procedure: To produce an accurate picture of performance, the PM automotive team brings out the test gear. Acceleration and braking are measured with either a Stalker radar gun or GPS-based Racelogic Vbox. Handling tests require optical timers. Ben Stewart (not shown) and Larry Webster (above) run down the pretest checklist, ensuring proper fluid levels and setting every car's tires to the factory-recommended pressure.

Nissan Altima

Fuel Economy Champ
Inching up in sales volume for the past half-decade, the Altima has become a thorn in the side of Honda and Toyota. Restyled for 2010, the Nissan is the lightest car here by 100 pounds. And engineering out the excess weight in a design is the gift that keeps giving. The Altima was the quickest to 60 mph (7.72 seconds) and returned the best fuel economy (32.4 mpg).

While the scales suggest a flimsy structure, the Altima feels solid and well-built. The interior layout is refreshingly simple, with high-quality materials used throughout. The Altima's continuously variable transmission (CVT), the only available transmission, was not our favorite. The engine has plenty of torque, but it drones in the upper rev range, an unpleasant aspect that the CVT intensifies. But at least there is a manual mode, and we tended to use it during spirited driving.

The Altima was a little reluctant to change direction, with excess body roll and slower steering than, say, the Mazda. It doesn't want to hustle. But around town, outside the confines of our test course, we found the Altima to be very refined and comfortable.

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Toyota Camry

The Country's Best-Selling Car
Since the beginning of this century, the Camry has been the country's best-selling car more years than not. It's sensible, roomy and well-built. But driving the Camry is a slightly less exciting activity than toasting a piece of Wonder bread. Frankly, we need more fiber.

It's not that the Camry doesn't do its job effectively. It was one of the quicker sedans, yet still delivered an above-average 31.5 mpg. It's also exceptionally quiet and serene inside. Only the Honda Accord has a roomier back seat.

The interior that was once lauded for its quality feel now seems cheaply made, with poor panel fitment and low-rent materials. To be fair, the Camry is value-priced, but it's also the only one riding on 16-inch wheels with hubcaps.

We could forgive those sins, but the rest of the car is a big slice of ho-hum. If you push the Camry hard, the connection between man and machine feels as though it's separated by a layer of molasses. Its pillowy body motions reminded us of yesteryear's land yachts. If there's a payoff to this performance, it's the extremely plush ride and hushed interior.

The Camry sealed its reputation some two decades ago with a reliable and competent sedan in a market filled with lackluster cars. The world has caught up, and Toyota has faltered. The Camry was recalled in January and its production halted to fix a sticky throttle. It's time for Toyota engineers to remind us why the Camry deserves its top-selling status.

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