While the typical hybrid car is all about maximizing mpg, luxury hybrids have a more complicated mission. They cater to well-heeled buyers who also want brisk acceleration, responsive handling and an elegant interior loaded with amenities. As a result, these high-end green machines are often quite enjoyable to drive, but the fuel-efficiency gains over their conventional, gasoline-only counterparts are often quite modest. The 2014 Lexus GS 450h is unique in that it offers the features and performance expected of a midsize luxury sedan while delivering the big fuel economy numbers that many hybrid shoppers expect.

Powering the 2014 Lexus GS 450h is a hybrid powertrain that combines a 3.5-liter gasoline V6 engine, two electric motor/generators and a trunk-mounted battery pack to provide a total system output of 338 horsepower. Of course, the real appeal here is the GS 450h's impressive fuel economy. With a combined EPA rating of 31 mpg, this Lexus shines as one of the most fuel-efficient models in the luxury sedan segment.

Evaluated solely as a midsize luxury sedan, the GS 450h also hits the mark. The GS is a pleasure to experience on the open road, with capable handling and a refined and quiet ride quality. The interior is one of the classiest you'll find with its high-quality materials and excellent build quality, and the backseat is sufficiently roomy for a pair of adults. Of course, a comprehensive set of standard and optional high-tech features awaits you as well.

Ultimately, the Lexus GS 450h sedan's main shortcoming is its price. When new, it costs over $10,000 more than a similarly equipped GS 350. That price premium would take decades to recoup in gas savings. Even if you're not one to crunch the numbers, it's worthwhile to check out some of the other options for a fuel-efficient midsize luxury sedan, including the sporty new Acura RLX Sport Hybrid, the capable Audi A6 TDI and BMW 535d diesels and the more affordable Infiniti Q50 Hybrid. There are also the diesel and hybrid versions of the luxurious Mercedes-Benz E-Class.

Each car here has its own set of strengths, but if you like the idea of driving a luxury sedan that provides high levels of performance and refinement -- and posts impressive mpg every time you fill up -- the 2014 Lexus GS 450h is a fine choice.

The 2014 Lexus GS 450h is the hybrid version of the regular GS 350 sedan, which is reviewed separately. There is only one body style and trim level available.

Standard equipment includes 17-inch wheels, an adaptive suspension, adjustable drive settings, automatic LED headlights, LED running lights, heated and auto-dimming mirrors, automatic wipers, a sunroof and keyless ignition/entry. Inside the cabin you get cruise control, dual-zone automatic climate control, heated and ventilated eight-way power front seats with lumbar adjustment, driver memory functions, leather upholstery, a heated power-adjustable tilt-and-telescoping steering wheel and a power rear sunshade. Electronic features include Bluetooth phone and audio connectivity, a rearview camera, the Safety Connect emergency communications service and a 12-speaker surround-sound audio system with a six-CD changer, satellite radio, an auxiliary audio jack and an iPod/USB audio interface.

The optional navigation system brings with it a larger 12.3-inch central display screen, voice controls and the Enform suite of smartphone app features. The Luxury package adds 18-inch wheels, LED foglights, adaptive headlights, additional front seat adjustments, rear climate and audio controls, manual rear side sunshades, and upgraded leather upholstery and wood trim. The Luxury package can also be had with heated rear seats.

Stand-alone options include different 18-inch wheels, an automated parallel parking system, an active lane-departure prevention system, adaptive cruise control and a forward collision warning system, blind-spot monitoring, a head-up display, a power trunk opener and a premium Mark Levinson 17-speaker audio system.

Powering the 2014 Lexus GS 450h is a hybrid system composed of a 3.5-liter gasoline V6 engine and a pair of electric motor/generators fed by a trunk-mounted nickel-metal hydride battery pack. A total system output of 338 hp is sent to the rear wheels through a CVT.

At our test facility, we clocked the GS 450h from zero to 60 mph in 6 seconds, which is actually two tenths of a second slower than the last Lexus GS 350 we tested. The EPA's estimated fuel economy is very good at 31 mpg combined (29 mpg city/34 mpg highway). We validated this estimate by earning exactly 31 mpg on Edmunds' own 116-mile evaluation loop.

Every 2014 Lexus GS 450h comes standard with antilock brakes, traction and stability control, a rearview camera, front and rear side airbags, side curtain airbags and front knee airbags. Also standard is the Lexus Safety Connect system, which includes automatic collision notification, an emergency assist button and stolen vehicle location services.

Optional features include blind-spot monitoring (with rear cross-traffic alert) and a lane-departure warning system that can steer you back into place should you fail to act. Adding the optional adaptive cruise control includes a frontal collision warning system that detects an impending collision and responds by pre-tensioning the seatbelts and activating brake assist.

In Edmunds brake tests, we measured a 122-foot stop from 60 mph, which is average for a luxury sedan with all-season tires.

Though the GS 450h has not been tested specifically, the Insurance Institute for Highway Safety gave its gasoline-only equivalent, the GS 350, the best possible rating of "Good" in the moderate-overlap frontal-offset, side-impact and roof strength tests. Seat and head restraint design were also rated "Good" for whiplash protection in rear impacts. There is no comparable government crash data from the National Highway Transportation Safety Administration.

As expected of a hybrid luxury sedan, the 2014 Lexus GS 450h goes about its business silently and efficiently, wrapping its occupants in a cocoon of serenity. Acceleration is quick, though enhanced fuel economy is the 450h's main reason for existence. In our testing the hybrid was actually a bit slower than the regular GS 350.

The hybrid GS sedan's standard adaptive suspension continually adapts to road and driving conditions to provide the best ride and handling possible. A driver-adjustable interface includes Eco, Normal, Sport and Sport Plus settings, and in addition to the suspension, you can tailor the car's steering effort, accelerator response and stability control intervention to your liking, although the latter is still set to very conservative limits. Just want that silent and efficient commute? Stick with Eco or Normal. Feeling feisty or want to show your BMW-owning buddy that hybrids can have some fun, too? Dial up Sport Plus. There's also an EV mode that enables you to drive for short distances at low speeds on battery power alone.

In the best Lexus tradition, the GS 350h features a finely crafted interior marked by soft leather and rich wood and aluminum trim. Befitting this caliber of luxury sport sedan are seats that are firm and cosseting in equal measure, and limited only by the degree of power adjustments you choose. In back, two average-sized adults should be pretty comfortable, though the BMW 5 Series is roomier still.

The GS 350's Remote Touch multimedia controller is more problematic. This small, mouselike device adjacent to the gear selector makes sense conceptually, but cursor control is wobbly and imprecise, and making audio or navigation selections is even harder when you're on the move. Further complicating the process is the system's lack of a physical "back" button and the fact that all the icons are the same color. That said, we do like the impressively large 12-inch display that comes with the optional navigation system as well as the optional Mark Levinson audio system, which sounds fantastic.

Total luggage capacity for the trunk measures 13.2 cubic feet, just a bit less than the regular GS 350. Still, most conventional midsize luxury sedans have bigger trunks with rear seatbacks that fold to expand potential cargo capacity. As in the GS 350, the GS 450h's rear seats don't fold down.