Inside, the goal was to "surprise and delight"—and the XF has several unique features. Push-button ignitions are becoming a luxury-car cliché, but the XF's pulses red like a heartbeat when it senses the key nearby. Once you start the engine, a silver rotary knob rises from the console—it's a simple, elegant transmission selector—and blank plates on the dash rotate to reveal air vents. The interior light requires nothing as crude as a switch; moving a finger over them triggers the row of lights, one by one.

Reviews of the XF in both the enthusiast press and general media have been ecstatic. Auto journalists have lauded the styling, the roadholding, the level of standard equipment—all XFs sold in the U.S. include a V8, leather upholstery, 19-inch wheels, and iPod compatibility—and most of all, the car's distinctive look. Britain's Car magazine gushed, "Even Aston owners don't get to enjoy an interior as special as the XF's."

Thus far, sales have exceeded the company's projections—by a healthy margin. "People come in enthusiastic, but then they see it, and they just fall in love with the car," says Beau Boeckman, president of Galpin Jaguar in Van Nuys, California.

As of May 31, Jaguar had sold 3,500 XFs in the U.S., says Craig Samara, the company's vice president of retail operations, with 700 more ordered. At 1,200 a month, the XF now actually outsells Audi's A6 and Volvo's S80—though not the segment-leading BMW 5 Series and Mercedes-Benz E-Class. Crucially, almost four times as many XFs sold this May as S-Types sold last May.

More importantly, the XF is bringing new buyers to Jaguar. So-called "conquest buyers" represent 60 percent of the total, far higher than Jaguar had projected. The average age of XF buyers is 48, a full decade younger than Jaguar's average last year.

Dave Leggett, of British industry analyst Just-Auto, says it remains to be seen "whether the car is good enough to get BMW and Mercedes-Benz buyers out of their cars" over the long term. Past the first wave of enthusiasm, Jaguar will find out whether it has overcome its stodgy brand image among enough 35- to 50-year-old buyers.

"Jaguar has been making capable cars for several years; they've got their dealers and their servicing sorted out, but they're viewed as staid and archaic," said Global Insight's Bragman. He questions whether the XF is radical enough.

The next salvo in Jaguar's attack will be a restyled large XJ sedan, to be launched for 2010. It will be "even more of a departure," says Bragman.