If you're shopping for a large luxury sedan, it's pretty much obligatory to check out the 2015 BMW 7 Series. The 7 Series has been a popular choice for decades, thanks to its mix of performance, driver involvement and cosseting luxury. But because of some newer, flashier rivals, the big BMW may not feel as special as it once did.

Certainly, there's nothing wrong with what's under the hood. The six-cylinder (740i) and V8 (750i) engines are strong, and BMW has further expanded the 7 Series line for 2015 with the addition of a turbocharged 3.0-liter diesel inline-6 engine. Available only in long-wheelbase, all-wheel-drive 740Ld xDrive trim, the diesel is capable of an EPA-estimated 26 mpg combined. Another strength is the BMW iDrive infotainment system, which is easy to use, has clear graphics and requires less driver attention than some competing systems. If you plan on spending most of your time in the backseat, there's an optional iDrive system for the rear passengers, too.

Lately, though, the 7 Series has started to seem a bit dated. The cabin may be exquisitely trimmed and generously equipped, but its design is hardly groundbreaking by current standards. Also, most of the 7's interior touches can be found in the smaller, less expensive BMW 5 Series, which takes a bite out of the bigger car's exclusivity. In terms of handling, the 7 Series is no longer a class leader, having been eclipsed by multiple performance-oriented rivals. And you may have to pack light for road trips, as the trunk measures a relatively measly 14 cubic feet.

If you're shopping around, you'll find that the innovative 2015 Mercedes S-Class is the most luxurious (and arguably most prestigious) in this segment. On the other end of the spectrum, the 2015 Porsche Panamera outdoes the 7 Series with stunning handling abilities and a comparable selection of engines. Both the extroverted 2015 Jaguar XJ and the understated 2015 Audi A8 are also a bit more involving, and the Audi has a particularly well-executed interior.

It's hard to call the 2015 BMW 7 Series disappointing by any measure, as it is still a truly amazing car, but some newer flagship luxury sedans may get your heart beating a bit faster.

The 2015 BMW 7 Series is a full-size luxury sedan. It comes in three trim levels: 740, 750 and 760. The 740 and 750 are available in two wheelbase lengths: "i" for normal and "Li" or "Ld" for long. The 760 is offered only with the long wheelbase. Two other variants, the ActiveHybrid 7 and the Alpina B7, are reviewed separately.

The 740 comes standard with 18-inch wheels, adaptive dampers, a self-leveling rear air suspension, adjustable drive settings, xenon headlights (automatic, adaptive and self-leveling), LED foglamps, automatic wipers, power-folding and auto-dimming heated mirrors, a sunroof, front and rear parking sensors, a rearview camera and keyless ignition/entry.

Standard interior equipment includes four-zone automatic climate control, cruise control, an auto-dimming rearview mirror, leather upholstery and heated power front seats with four-way lumbar adjustment and memory functions. Technology features include a digital instrument panel, the iDrive interface with touchpad functionality and a central widescreen display, Bluetooth phone and audio connectivity, a navigation system, voice controls, BMW Assist emergency communications, BMW Apps smartphone integration and a 12-speaker sound system with a CD player, an auxiliary audio jack, an iPod/USB audio interface, HD radio, satellite radio and 20GB of digital music storage.

An optional Lighting package for the 740 adds LED headlights with automatic high beams.

The 750 comes standard with 19-inch wheels (18s are a no-cost option), the Lighting package, power-closing doors, a power trunk lid with a foot sensor, a head-up display, 16-way power multicontour front seats (with adjustable side bolsters and four-way lumbar), upgraded leather upholstery with extended coverage and a 16-speaker Harman Kardon surround-sound audio system.

Both the 740 and 750 are eligible for an Executive package. The 740's version includes most of the 750's extra standard features plus ventilated front seats. The 750's version includes the ventilated seats and adds power rear and manual rear side sunshades, ceramic-trimmed controls and a simulated-suede headliner (all optional on the 740).

There are a couple more packages available on both the 740 and 750. The Cold Weather package includes heated rear seats, a heated steering wheel and a trunk pass-through ski bag. The Driver Assistance Plus package adds blind spot monitoring, lane departure warning, a drowsiness monitor, side- and top-view parking cameras and a speed-limit display.

Other options on these trims include an enhanced adaptive suspension (Adaptive Drive with Active Roll Stabilization), rear steering (Integral Active Steering) and massaging front seats.

The 760Li comes standard with all of the above optional equipment except the simulated-suede headliner (don't worry, it's available). It also includes burl walnut trim and power-adjustable rear seats with four-way lumbar adjustment, heating and ventilation (optional on 740Li and 750Li).

Optional on all long-wheelbase 7 Series models is massage functionality for the rear seats.

Every 7 Series can be equipped with an M Sport package that includes 19- or 20-inch wheels, a sport steering wheel, unique exterior styling elements, a faux-suede headliner (included on 760Li M Sport, optional on the others) in a variety of colors and a higher top speed. Other options include the Individual Composition luxury trim package with numerous customization opportunities, a self-parking system (not available with all-wheel drive), adaptive cruise control with a forward collision mitigation system, a night-vision pedestrian-detection system, a 16-speaker Bang & Olufsen sound system and a rear seat entertainment system with dual screens and an iDrive controller.

The 2015 BMW 7 Series comes standard with rear-wheel drive and an eight-speed automatic transmission. BMW's xDrive all-wheel drive comes standard on the 740Ld and is optional on 740Li and 750 models. All 7 Series models except the 760 feature an automatic stop-start system that turns off the engine when the car is stopped to save fuel. Depending on which 7 Series you decide on, EPA-estimated fuel economy will vary.

The 740i and 740Li are powered by a turbocharged 3.0-liter inline six-cylinder engine that produces 315 horsepower and 330 pound-feet of torque. BMW estimates that rear-wheel-drive versions will go from zero to 60 mph in 5.6 seconds, while the 740Li xDrive drops to 5.4 seconds. EPA fuel economy estimates are 23 mpg combined (19 city/29 highway) with rear-wheel drive and 22 mpg combined (19/28) for the 740Li xDrive.

For the new 740Ld xDrive, there's a turbocharged 3.0-liter diesel engine that puts out 255 hp and 413 lb-ft of torque. BMW estimates that the diesel 7 will go from zero to 60 mph in 6.1 seconds. EPA estimated fuel economy for the 740Ld tops the 7 Series range at 26 mpg combined (23/31).

The 750 gets a turbocharged 4.4-liter V8 engine that pumps out 445 hp and 480 lb-ft of torque. BMW estimates that the rear-wheel-drive 750i will hit 60 mph in 4.7 seconds; adding xDrive shaves a tenth of a second. EPA estimated fuel economy for the 750i checks in at 20 mpg combined (17/25), while the 750Li drops to 19 mpg combined (16/25). Both xDrive versions get 19 mpg combined (16/24).

Finally, the 760Li boasts a 6.0-liter turbocharged V12 that produces 535 hp and 550 lb-ft of torque. BMW says it will hit 60 mph in 4.5 seconds, which is barely quicker than the 750i, but in real-world driving, the V12 feels more potent than the V8. As expected, the V12 returns the lowest fuel economy of the bunch, at 15 mpg combined (13/20).

All 2015 BMW 7 Series models come standard with antilock brakes, traction and stability control, front side airbags, full-length side curtain airbags, front knee airbags and active front head restraints. Also standard is the BMW Assist emergency communications system, which includes automatic crash notification, an emergency response button, remote door unlock and stolen vehicle recovery. Multiple parking cameras, a blind spot warning system, a lane departure warning system, park assist, a drowsiness monitor and a collision mitigation system with automatic braking are available (mainly via the Driver Assistance Plus package).

In Edmunds brake testing, the 740i stopped from 60 mph in 109 feet, which is excellent for such a heavy car with all-season tires. The heavier 750i needed 118 feet.

Despite weighing well over 2 tons, even the entry-level BMW 7 Series is still a quick car. The gasoline-powered inline-6 provides an impressive swell of midrange torque, and it produces a sub-6-second sprint to 60 mph that's competitive for the segment, even among more recently updated models. The new 740Ld xDrive feels even stronger and provides superior fuel economy to boot.

Still, the V8 (750) and V12 (760) engines are far more suitable for a big sedan like this. When the turbos spool up in either car -- and it doesn't take long -- it's as if a gale-force wind from the car gods has suddenly hit your sails. The V12 wins on sheer coolness, but it's available only in a pricey and somewhat awkward-looking long-wheelbase trim. For most owners, the 750's V8 will be a source of endless entertainment (and for the depraved few who aren't quite as impressed, there's always the Alpina B7).

While BMW is typically known for its impressive driving dynamics, the 7 Series is more focused on comfort. It is an accomplished handler by the numbers, but it's just not especially communicative or engaging, whereas rivals like the XJ, Panamera and Maserati Quattroporte seek to draw you into the driving experience.

The main point of a big luxury sedan, however, is arguably to cosset its occupants over long distances, and by this measure the 7 Series verges on a perfect 10. It glides down the highway with quiet confidence, making any speed you select seem too slow. The adjustable drive settings are a significant asset here, subtly changing the car's character to suit surface and pace.

BMW typically resists the latest trends in dashboard design, sticking instead with classic gauges and an understated center stack that cants toward the driver. That's the case with the 2015 7 Series, and it lends a refined, sophisticated character to the cabin. But unlike the S-Class, for example, the 7 Series' interior layout is not unique, as the less expensive 5 Series employs much the same dashboard and features. Even the iDrive infotainment system's slick new touchpad with fingertip-scribble recognition isn't an exclusive feature -- it's standard on many other BMWs, too.

To call the 7 Series interior subpar would be a bit harsh, though. The 7's supple leather, rich wood accents and other high-quality materials assure a suitably premium feel. Comfort is pretty much beyond reproach, especially if you opt for the multicontour front seats with their incredible support and range of adjustments. The rear seats are plenty spacious by default, but the extra 6 inches of length in the long-wheelbase models comes in handy if you want to cross your legs. Available power rear seats with heating, cooling and massage provide further incentive to let someone else ride up front, though you'll find even more rear seat accoutrements in some rivals.

The 7's trunk measures 14 cubic feet, an unimpressive figure for this class.