The 2015 BMW 5 Series is a comfortable, technologically advanced midsize luxury sedan with a very appealing set of skills.Vehicle overviewThe 2015 BMW 5 Series marks the fifth year of a somewhat controversial experiment. Before the current 5 Series debuted for 2011, BMW's midsize sedan was the benchmark for handling precision and driving satisfaction. But was that what customers really wanted? The company's product planners weren't convinced. So they tried a different tack this time, substituting size and comfort for cutting-edge athleticism -- and polarizing public opinion in the process.Those who prophesied doom for the softer, friendlier 5 Series have, of course, been proven wrong, as the 5 Series continues to be a top draw for numerous reasons. You'll find a lot to like under the hood, from the 528i's overachieving turbocharged four-cylinder engine to the 550i's awesome twin-turbo V8 -- and don't forget about the 535i's accomplished turbocharged inline-6 and the 535d's ultra-efficient six-cylinder diesel. Meanwhile, the cabin is an expert show of restrained, finely wrought luxury, with an appealing array of up-to-date technology offerings. Really, the only thing missing is the rewarding handling of yore, but for many shoppers, the 5 Series' space and comfort will be more than adequate compensation.Should you desire more sport in your sport sedan, a number of competitors have stepped up to fill the void. The 2015 Audi A6 feels notably lighter on its feet and competes well in the powertrain department, too. We're also fond of the impressively sporty Cadillac CTS and the polished 2015 Lexus GS 350. For a traditional luxury experience, the 2015 Mercedes-Benz E-Class beckons, while the Jaguar XF holds dark-horse appeal, making up for its dated interior with spirited performance and a distinctive character. But the 2015 5 Series remains an excellent all-around luxury sedan, and that's why it's still at the head of this hotly contested class.2015 BMW 5 Series modelsThe 2015 BMW 5 Series is a midsize luxury sedan available in four main trim levels that correspond to engine choice: 528i, 535i, 535d and 550i. Rear-wheel drive is standard, with xDrive all-wheel drive optional across the board. The ActiveHybrid 5 and high-performance M5 models are reviewed separately.The base 528i starts with the four-cylinder engine, 17-inch wheels, adjustable drive settings (for steering, throttle and automatic transmission response), adaptive xenon headlights with LED accent lights, LED foglights, adaptive brake lights, automatic wipers, heated mirrors, a sunroof, cruise control and auto-dimming mirrors. Inside there's dual-zone automatic climate control, dark wood trim, ambient lighting, 10-way power front seats (with four-way power lumbar), driver memory functions, split-folding rear seats, leatherette premium vinyl upholstery and a power tilt-and-telescoping leather-wrapped steering wheel. Technology features include BMW Assist emergency communications, the iDrive electronics interface (with a 10.2-inch widescreen display and smartphone app integration), a navigation system, Bluetooth phone and audio connectivity, and a 10-speaker sound system with a CD player, HD radio, an auxiliary audio jack and a USB port.The 535i adds a six-cylinder engine, 18-inch wheels and leather upholstery, but is otherwise similarly equipped.The 535d is equipped exactly like the 535i, only with a diesel-powered six-cylinder engine.The 550i upgrades to a V8 engine, a hands-free power trunk lid (opening or closing automatically when you pass your foot under the rear bumper), keyless entry and ignition, a sport version of the automatic transmission with steering-wheel-mounted shift paddles, front and rear parking sensors, a rearview camera and 20-way multicontour power front seats (with four-way power lumbar).Engines aside, the standard features on the higher trims can be added to lower trims as options. Notably, the Premium package (528i, 535i and 535d) includes the hands-free power trunk lid, keyless entry and ignition, satellite radio and (for the 528i) leather upholstery. The 550i offers the Executive package, which adds soft-closing doors, ceramic-trimmed interior controls, a leather dashboard, a head-up display, an upgraded instrument cluster display and a 16-speaker Harman Kardon audio system with satellite radio. Most of the Executive package's contents can be added as individual options to lesser trims.There are two major equipment lines available on 2015 BMW 5 Series models: Luxury and M Sport. The Luxury Line includes 18-inch (528i) or 19-inch wheels, upgraded leather upholstery and anthracite wood trim. The M Sport includes staggered-width 18-inch (528i) or 19-inch wheels, shadowline dark exterior trim (instead of the default chrome accents), an aerodynamic body kit, aluminum interior trim, a dark headliner and an M steering wheel. The Individual Composition package (not available