(This review was originally written for the 2009 Jaguar XF. Since little of significance has changed it has been updated to include the 2010 and 2011 model years.)

The 2009 Jaguar XF is a five-passenger four-door sedan introduced in March 2008 to go up against other brands in the highly competitive premium midsize class that includes the BMW 5-Series, Audi A6, Infiniti M, Mercedes-Benz E Class, Lexus GS, and Cadillac CTS.

After years of paying homage to highbrow British tradition, the strikingly handsome XF signals a shift in direction for the marquee brand. So far the results haven’t been a hit. While overall Jaguar sales increased 9.5 percent in the first half of 2011, led by the all-new flagship XJ model, XF sales have declined 36.6 percent.

Based on the XK coupe, the XF’s look is a big departure from the S-Type sedan it replaced. The exterior is sleek, with swooping lines and a strong stance thanks to short front and rear overhangs. Not once was it immediately identified as a Jaguar by people we ran into during our weeklong test drive as only the leaping chrome cat on the rear deck lid and Jaguar nameplate on the front fender vent gills announce the maker.

The front of the XF seems most out of place. The large mesh grille seems rather garish, and would be more at home on a Buick or Chrysler. Also, the headlamps seem disconnected from the design, with large gaps around the entire assembly.

The most striking thing about the new XF is the interior, however. This car’s cabin rivals anything in its class — other than Audi — and is loaded with modern innovation to the point of excess.

Slip behind the wheel and the start button on the center console begins to pulse red, “like a heartbeat,” according to Jaguar. Press the button and the “beast comes to life.” The XF gearshift selector begins to rise out of the console so you can dial into drive or reverse. Pushing the start-stop button automatically returns the car to park, and the gearshift returns to its secluded home.

Simultaneously, the navigation system automatically boots up its home page and the brushed aluminum dash vents automatically rotate to the open position, closing again when the vehicle is shut down.

Overhead lighting and the glove box are operated by proximity sensors rather than push buttons, a feature Jaguar calls “JaguarSense.”

Phosphor blue mood lighting illuminates and outlines the instrument panel controls, rotary gearshift, and door handles. All interior materials are top quality, with soft-grained leathers and real wood veneers to compliment the textured aluminum highlights of the instrument panel and center console. Overdone and gimmicky? Perhaps, but it works well.

Front and rear occupant room is ample and front seats are sculpted for additional space and comfort. Even with the front seats all the way back there’s still legroom for rear passengers. The rear seat only has head restraints for two passengers and the pull-down center armrest is just a cup holder, with no storage capability. Trunk space is near the top of the class.

The audio system comes from high-end British company Bowers & Wilkens, the first time the company’s speakers have been used in a vehicle. It didn’t offer standout sound quality like a Bose or Rockford-Fosgate system, however.

Changes for the 2010 model year included the addition of the XF Premium, XF Supercharged, and high-performance XFR models. Along with the more powerful engines, the XFR also boasts quicker steering, bigger brakes, 20-inch wheels, unique exterior and interior styling and trim and automatically adjustable suspension damper settings for optimized ride and handling.

For 2011, XF is available in a choice of four models, the base XF at $52,500, XF Premium at $56,500, XF Premium with Portfolio Package at $60,500, and the XF Supercharged at $67,600. The base and Premium models are powered by a 5.0-liter, 385-horsepower V-8. The Supercharged model puts out 470-horsepower. The ultra-high performance XFR with a base price of $79,600 is a 510-horsepower monster that goes 0-60 mph in just 4.7 seconds. The larger, more powerful 5.0-liter engines have replaced the 4.2-liter V-8 in all XF models. All XF models feature a six-speed automatic transmission as the only choice.

Other changes for 2011 include larger front brakes and Jaguar Drive Control dynamic mode, a system that provides sportier settings for the suspension, throttle and transmission points. A heated windshield is also now available.

In 2011, we drove the base XF with the 385-horsepower engine with 380 foot-pounds of torque. It was blast to drive. Performance was more than adequate, and acceleration incredibly smooth. Yet it didn’t stand out from any of the other cars in this class of vehicle. Fuel consumption was higher than would be expected.

Handling is generally agile, predictable, and confident, even if it doesn’t have the surefootedness and stability of, say, a BMW. Perhaps it was the low profile tires on our tester, but we found the suspension unusually harsh with minor road surface imperfections amplified to the driver and occupants.

All expected safety features for a premium luxury sedan are standard, including dual-stage front airbags, front-seat side-impact airbags, and curtain airbags for front and rear side-impact protection, standard active head restraints, electronic stability system, and optional adaptive cruise control. Neither the insurance industry nor the federal government has crash tested the new XF as of this writing.

Now in its third year of production, and soon to be in its fourth, the XF sedan remains a far superior sedan to the vehicle it replaced, the S-Type. The XF remains one of the better-looking vehicles we’ve driven and its blend of high performance, signature British interior ambience and sophistication sets it apart from class competition, and it should be on your “must drive” list if shopping for a vehicle in this class.