Luxury sedan shoppers have come to expect quite a bit from automakers, and not every model is up to the task. But the 2015 Audi A6 is good enough to satisfy almost anyone's expectations. A strong performer in every category, the A6 spoils drivers and passengers alike -- and looks good doing it. If you're fortunate enough to be shopping in this all-star segment, the A6 belongs at the top of your test-drive agenda.

What makes the A6 such an excellent choice? Credit Audi's exacting standards across the board. The engines deliver exemplary refinement and performance that feels stronger than the numbers suggest. We're particularly enamored of the diesel-fueled TDI model, which earned an Edmunds "A" rating thanks to its phenomenal blend of fuel economy and acceleration. Regardless of which A6 you choose, you'll enjoy a hushed and upscale environment on the inside, with ample space, exquisite materials and cutting-edge technology. And on the road, the A6 feels remarkably nimble and athletic.

Although the A6 is easily one of our favorites in this class, there's still some strong competition out there. The 2015 BMW 5 Series isn't as sporty, but its engines, features and build quality stack up very well. Much the same can be said of the 2015 Mercedes-Benz E-Class, though its four-cylinder diesel's power output trails the six-cylinder versions from Audi and BMW. The 2015 Cadillac CTS's distinctive style and sports-car handling make it a worthy alternative to the Germans, while the Lexus GS 350 and the hybrid-powered Lexus GS 450h deliver world-class driving dynamics and interior decor. For a midsize luxury sedan that's good at everything, though, it's hard to beat the 2015 Audi A6.

The 2015 Audi A6 is a midsize luxury sedan essentially available in six trim levels -- 2.0T Premium, 2.0T Premium Plus, 3.0T Premium Plus, 3.0T Prestige, TDI Premium Plus and TDI Prestige. The 2.0T, 3.0T and TDI designations denote the engine fitted (a turbocharged 2.0-liter four-cylinder, a supercharged 3.0-liter V6 and a turbocharged 3.0-liter diesel V6, respectively). The high-performance S6 variant is reviewed separately.

Standard equipment for the 2.0T Premium includes 18-inch wheels, Audi Drive Select (providing adjustable modes for steering, gas pedal and transmission response), automatic xenon headlights, LED running lights and taillights, automatic wipers, auto-dimming mirrors, a sunroof, tri-zone automatic climate control, heated eight-way power front seats (includes four-way lumbar adjustments), driver memory settings, leather upholstery, Bluetooth phone connectivity, Audi's MMI electronics interface, a 6.5-inch display screen and a 10-speaker sound system with a CD player, satellite radio and an iPod interface. Also standard is Audi's Pre-Sense Basic safety system.

The 2.0T Premium Plus adds front and rear parking sensors, a rearview camera, a blind spot monitoring system, Pre-Sense Rear, power-folding exterior mirrors, keyless ignition and entry, an 8-inch display screen, a voice-activated navigation system, a rearview camera, HD radio, Bluetooth audio connectivity, an upgraded version of MMI with an enhanced controller and Audi Connect (featuring Google Earth integration, Google-powered search functions, smartphone app integration and WiFi hotspot capability).

The 3.0T Premium Plus is equipped similarly to the 2.0T Premium Plus but adds "S line" exterior enhancements and a fuel-saving engine stop-start system.

Going with the 3.0T Prestige gets you adaptive LED headlights, ambient LED cabin lighting, a head-up display, ventilated front seats, a power-adjustable steering wheel, a 14-speaker Bose audio system and the Warm Weather package (including four-zone climate control, a power rear sunshade and manual rear side-window sunshades).

The TDI Premium Plus is equipped similarly to the 3.0T Premium Plus, while the TDI Prestige has the same equipment as the 3.0T Prestige.

Optional packages, depending on trim, include the Warm Weather package (see above), the Cold Weather package (heated rear seats and a heated steering wheel), the Sport package (19- or 20-inch wheels, a sport-tuned suspension and a three-spoke sport steering wheel with shift paddles), the Driver Assistance package (adaptive cruise control, a top-view camera system with front and rear corner views, lane-keeping assist and Pre-Sense Plus collision mitigation with automatic braking) and the Black Optic package (high-gloss black trim and unique 20-inch wheels with summer tires).

Some of the higher trims' standard features are optional on lower trims, such as the Prestige's Bose audio system and LED headlights. Other notable options include rear side airbags and two items that are limited to the Prestige: a night vision camera system with pedestrian detection and a 15-speaker Bang & Olufsen audio system.

The 2015 Audi A6 2.0T is powered by a turbocharged 2.0-liter four-cylinder engine good for 220 horsepower and 258 pound-feet of torque. Front-wheel drive and a continuously variable automatic transmission (CVT) are standard, but you're more likely to encounter the all-wheel-drive version, which comes with an eight-speed conventional automatic. Audi estimates a 0-60-mph time of 7.4 seconds with the CVT and 6.6 seconds with the eight-speed. Fuel economy for the 2.0T is EPA rated at a laudable 28 mpg combined (25 city/33 highway) with the CVT, dropping to a rather pedestrian 23 mpg combined (20/29) with the eight-speed.

The Audi A6 3.0T gets a supercharged 3.0-liter V6 that produces 310 hp and 325 lb-ft of torque. The eight-speed automatic and all-wheel drive are standard, as is automatic engine stop-start technology. In Edmunds performance testing, the 3.0T sedan went from zero to 60 mph in 5.2 seconds, a quick time among midsize luxury sedans equipped with similarly powerful six-cylinder engines. Fuel economy stands at an estimated 22 mpg combined (18/27), just a tick behind the much less powerful 2.0T.

With the A6 TDI, you get the best of both worlds. The all-wheel-drive TDI's 3.0-liter turbodiesel V6 cranks out 240 hp and 428 lb-ft of torque, teaming up with the eight-speed auto. The combo was good enough to hit 60 mph in just 5.6 seconds in our testing. Yet fuel economy is a stellar 29 mpg combined (24/38), ranking right up there with frugal compact sedans. In an Edmunds test over 400 miles with varying driving conditions, we averaged 27.8 mpg.

Standard safety equipment on the 2015 Audi A6 includes antilock disc brakes, stability control, front-seat side airbags, front knee airbags and full-length side curtain airbags. Rear side airbags, a rearview camera, front and rear parking sensors, lane-keeping assist and a blind-spot warning system are optional.

The standard Audi Pre-Sense system can warn the driver, tension the seatbelts and close the windows if a potential collision is detected, while Pre-Sense Rear flashes the brake lights as a warning to rearward traffic if you're in danger of being rear-ended. The optional Pre-Sense Plus system (available via the Driver Assistance package) can do all that, plus fully tighten the seatbelts and automatically apply the brakes full force to mitigate crash damage from an impending frontal collision.

In Edmunds brake testing, an A6 3.0T with the Sport package's summer performance tires came to a stop from 60 mph in 111 feet, while an A6 TDI Sport with summer tires did it in 114 feet. These are average distances among comparably equipped midsize luxury sedans. Expect longer distances from A6s with all-season tires.

In government crash tests, the 2015 Audi A6 received five out of five stars overall, with five stars for frontal crash protection and five stars for side-impact protection. The independent Insurance Institute for Highway Safety gave the A6 its highest rating of "Good" in the moderate-overlap frontal-offset, side-impact and roof-strength tests, while the A6's seat and head restraint design was also rated "Good" for whiplash protection in rear impacts.

The 2015 Audi A6 is a fun car to drive, especially considering its size and heft. It changes directions eagerly, with plenty of grip from all four corners. Not many midsize luxury sedans forge such a gratifying connection with the driver. One demerit is overly light and numb steering under normal circumstances, but we've found that the effort tends to firm up as your enthusiasm increases.

The supercharged 3.0-liter V6 engine is responsive and pulls with effortless authority all the way to redline. The 2.0T doesn't sound quite as smooth, but it certainly feels stronger than the official 220-hp rating. The front-wheel-drive 2.0T Premium with its CVT is an oddball offering in this segment; although the CVT isn't bad for the breed, we much prefer the all-wheel-drive 2.0T Premium Plus with its confident conventional automatic, even though fuel economy suffers. Cost no object, the TDI is the pick of the litter, as it provides a mountain of torque and by far the best fuel economy.

Although the A6 has a composed ride that's never harsh, it's definitely firm, and there are sometimes more jolts than we'd like on rough pavement. For this reason, we recommend skipping the Sport package with its firmer suspension, especially if you're eyeing the 20-inch wheels. The regular A6 handles just fine, and it rides noticeably better with the standard 18s.

The 2015 Audi A6 has one of the best cabins in its class, with an attractive dash layout, excellent materials quality and solid fit and finish. The familiar MMI infotainment system controls a dizzying array of functions, utilizing a dash-mounted pop-up screen and a knob and buttons on the center console. The system boasts logical menus and crisp graphics, and the "MMI navigation plus" upgrade (standard on all except the base 2.0T Premium) includes a touchpad that can recognize fingertip scrawls. It's remarkably sophisticated, but we still prefer BMW's iDrive or Mercedes' COMAND for overall ease of use.

The upgraded MMI system also serves as a mobile 3G WiFi hotspot for up to eight devices, and it adds Google Earth data to the navigation system while providing a simplified Google search for POIs. The hotspot in particular is quite handy if you need to get some work done on the road and there's no Starbucks in sight. The Google Earth navigation system is more a matter of form over function, however, and can actually make the map more difficult to comprehend at a glance.

The A6's front seats are supportive and comfortable, remaining so even on long trips, though some may lament the absence of optional "super seats" like BMW's multicontour chairs. The spacious backseat offers more real-world legroom than most rivals. The A6's 14.1-cubic-foot trunk is slightly below average for the segment, but we've found it generous in real-world testing, and the rear seatbacks both fold and offer a pass-through when more space is needed.