Taking the road "less traveled" has its rewards, and the flagship XJ sedan, the full-size luxury offering from Jaguar, certainly goes down its own non-conformist path. It's neither as conservative-minded as the German marques nor as flamboyant as the Italian. The uniquely British direction in this particular segment of automotive indulgence might be characterized by the 2015 Jaguar XJ's elegant design and sophisticated presentation inside and out. Dynamically, it sets no records, but the XJ's performance achieves a different goal: effortless competence and pace. One part old-world elegance, one part modern sophistication, the XJ luxury sedan stands out in this prestigious crowd.

Offered in regular and long-wheelbase versions with rear- or all-wheel drive and a choice of three powerful supercharged engines, there's an XJ to suit a variety of budgets, climates and drivers -- or chauffeurs. Opting for a long-wheelbase version means the limousine-like sedan is eligible for an opulent rear-seating upgrade that includes twin power-operated rear seats with ventilation, heating and massage, plus an entertainment package and two laptop-sized business tables. Numerous comprehensive option packages further enhance either the level of luxurious amenities or increase the XJ's latent performance potential. There are even ways to combine these seemingly divergent qualities into one ultra-luxurious high-performance super "saloon," to borrow the vernacular.

Boasting a long list of standard features, even the base XJ is hardly roughing it. A 340-horsepower engine paired with an eight-speed automatic transmission propels the aluminum-bodied sedan while communicative steering helps drivers feel in control of this regal coach through turns. The self-leveling suspension and double-thickness laminated glass do their part to isolate the occupants from the outside world.

Stepping up to either a 470-hp engine of the XJ Supercharged or the XJR's 550 hp not only invigorates the driving experience but adds more standard equipment as well. Regardless of configuration, however, the XJ's high-fashion interior is one of the qualities that distinguish it from its Teutonic competition. Presentation is classy and eye-catching without falling into gaudy or gouache -- and certainly not cold and detached. And the fact that the XJ typically doesn't sell in the same numbers as its rivals also gives it an air of exclusivity.

So what are the downsides to owning a 2015 Jaguar XJ? Although the XJ's cabin is a feast for the eyes, the quality of construction isn't quite as bulletproof as its primary, German-brand competitors: the 2015 Audi A8, 2015 BMW 7 Series and 2015 Mercedes-Benz S-Class. Technology is another area where the XJ brings up the rear. Its touchscreen interface is less advanced and, ultimately, less functional than rival infotainment systems, and there are several high-tech features (especially in the active safety realm) that are not offered at all. The lack of a fuel-efficient diesel or hybrid version will be another drawback for some shoppers. As such, we've given the XJ an Edmunds "B" rating. However, for those of you who let your emotions rule your car buying decisions, the stylishly refined and, at times, quite exhilarating Jaguar XJ is bound to have lasting appeal.

The 2015 Jaguar XJ is a five-passenger full-size luxury sedan available in regular (XJ) and long-wheelbase (XJL) variants. The XJ comes in base, Supercharged and XJR models, while the XJL has the Portfolio, Supercharged and XJR models.

The base XJ comes standard with a supercharged V6, 19-inch wheels, an adaptive and self-leveling suspension, driver-adjustable steering and throttle settings, shift paddles, front and rear parking sensors, a rearview camera, automatic wipers, automatic bi-xenon headlights, auto-dimming mirrors, a panoramic sunroof and keyless ignition and entry.

Standard convenience equipment includes soft-close doors, a power trunk lid, dual-zone automatic climate control, heated eight-way power front seats (with four-way power lumbar), driver seat memory settings, a power tilt-and-telescoping heated steering wheel and heated rear seats.

An 8-inch touchscreen system anchors the multimedia features, augmented with a standard navigation system, Bluetooth phone and audio connectivity, voice controls and a 14-speaker Meridian audio system with a CD player, satellite radio, HD radio, digital music storage and a USB connection.

Adding to the base XJ, the Front Seat Comfort package includes heated and ventilated 14-way power front seats with massage functions and front passenger seat memory settings. The Portfolio package yields those features plus a faux suede headliner, dual-zone automatic climate control for the rear seats, heated and ventilated rear seats and extended leather upholstery. Opting for the Visibility package gets you adaptive headlights and automatic high-beam control. Choosing the Portfolio option also unlocks more exterior paint, interior trim and headliner material choices.

Opting for the long wheelbase on the base XJ requires you to order the XJL Portfolio configuration. Most Portfolio package features come standard on the XJL Portfolio. Along with the 4 inches of additional rear legroom, this model includes rear vanity mirrors and manual rear sunshades.

The same XJ option packages are available on the XJL Portfolio. You can also get a Rear Seat package with massaging rear seats, a special folding rear center armrest, front and rear winged headrests, driver control of the front passenger seat, and rear seat footrests. The Premium Rear Seat package additionally adds power rear sunshades and a rear seat entertainment system with dual displays.

Moving up to the XJ Supercharged brings a supercharged V8, along with an active rear differential, tauter suspension tuning, 20-inch wheels with performance tires, larger brakes, the Visibility package and a 20-speaker Meridian audio system. All of the XJL Portofolio options are available, plus a Sport and Speed Package that adds red brake calipers, a front splitter and deck lid spoiler, a higher top-speed limiter, exclusive exterior and interior trim details and 14-way sport seats. A long-wheelbase model is also offered.

Top of the heap is the XJR, available in regular and long-wheelbase versions, that comes with the most potent Jaguar V8 engine of all, exclusive 20-inch wheels, XJR-specific suspension tuning, a quad-tip exhaust and the contents of the Sport and Speed package.

Other options include a heated windshield, adaptive cruise control (with collision warning and automatic braking), a premium leather interior package and a 26-speaker Meridian surround-sound audio system.

The 2015 Jaguar XJ base and XJL Portfolio models feature a supercharged 3.0-liter V6 engine generating 340 hp and 332 pound-feet of torque. An eight-speed automatic transmission and rear-wheel drive are standard; all-wheel drive is optional.

EPA-estimated fuel economy is 21 mpg combined (18 city/27 highway) for the rear-drive model. The AWD model is rated at 19 mpg combined (16/24). On Edmunds' 120-mile mixed-driving evaluation route, we were impressed with the 24 mpg earned by an XJL Portfolio AWD.

Upgrading to the XJ Supercharged model gets you a supercharged 5.0-liter V8 with 470 hp and 424 lb-ft of torque, while the XJR extracts 550 hp and 502 lb-ft of torque from a higher-performance version of this engine. Both models return an EPA-estimated 18 mpg combined (15/23), and we coaxed 22 mpg from a long-wheelbase XJR on our evaluation route.

In Edmunds testing, a Jaguar XJR (LWB) accelerated from zero to 60 mph in just 4.1 seconds. An XJL Portfolio AWD required 6.1 seconds in our testing, which falls a little short of best-in-class acceleration.

Every 2015 Jaguar XJ comes standard with antilock brakes, stability and traction control, front side airbags, side curtain airbags, active head restraints, a rearview camera and a blind-spot warning system. A forward collision alert system and advanced brake assist (primes the brakes if an accident is imminent) are included with the optional adaptive cruise control.

In Edmunds brake testing, an XJL Portfolio with the standard 19-inch wheels and all-season tires stopped from 60 mph in 124 feet, a bit longer than average for this class of car. An XJL Supercharged with summer tires and its larger standard brakes, however, stopped from 60 mph in 106 feet. The similarly equipped XJR did it in 105 feet. Both distances are shorter than average for the segment.

Conspicuous in their absence are brakes that are automatically applied (if a collision is imminent), lane-keeping warning/assist, an automated parking system, surround-view cameras, a rear cross-traffic alert, a head-up display, speed limit information within the navigation system and night-vision capabilities. Many of these high-tech safety enhancements are either standard or available on other flagship sedans.

The Jaguar image is one of effortless pace, and the 2015 XJ's gracious road manners don't disappoint. Jaguar retuned the suspension last year to improve ride quality, and indeed, the big sedan rides better, even with larger wheels and tires. Quiet as they were, however, both the XJL Portfolio and XJR we drove still had trouble damping out harsh road impacts. Aluminum construction makes the XJ lighter than it looks, and the Jag has an agility that some rivals can't match. Driver-selectable settings for the engine and transmission provide discernible differences and enable softer or more aggressive responses from the driveline.

The supercharged V6 pulls effortlessly, offers decent fuel economy and will hit the sweet spot for most buyers. It sounds great, too. But if it's outright power you crave, either of the beefy supercharged V8 engines will deliver. The Jaguar XJR tops the lineup with the most power and a firmer suspension. While not punishing by any definition, the XJR is best suited to the driver who appreciates, and intends to exploit, its performance potential. The XJR isn't likely to be spotted at a track-day event, but this highest-performance model in the 2015 Jaguar XJ lineup is hugely satisfying when you crack the whip on the open road.

Settling into the elegant interior of the Jaguar XJ makes you realize just how austere and clinical other high-profile luxury sedans have become. But while presentation in the Jaguar is impressive with its high-quality leather surfaces set off with brilliant chrome and exquisite ambient lighting, the parts selection and overall build quality doesn't fulfill the promise of a flagship quality that competitors' similar sedans do. Liberal use of plastic and many parts clearly shared with other Jaguar cars takes away some of the special-ness of the top-tier XJ.

Old World luxury meets contemporary aesthetics with a digital instrument panel replicating mechanical dial indicators in a variety of user-configurable layouts and bathed in soothing ice blue and alternatively racy-red hues. The XJ's touchscreen interface commands most of the sound, navigation and phone controls. While its speed and operation has improved over the years, competitors' systems (typically manipulated via one large control dial and adjacent menu buttons) are easier and quicker to use and give the driver control over a wider array of vehicle functions.

Although its vast exterior profile suggests otherwise, the XJ's sloping roof line sacrifices both front- and rear-seat headroom for style. In the base models, there's also not as much legroom back there as you'd expect. If you need a roomy backseat, consider the long-wheelbase L models, but thankfully no XJ will feel as limolike as some of its competitors do. Similarly, the XJ's 15.2-cubic-foot trunk is average in size for the segment and has a few awkward protrusions as well as a shallow profile that limits your loading options.