Car shoppers looking at any vehicle with all-wheel drive (AWD) or four-wheel drive (4WD) as an option face a difficult decision. Is AWD that much safer and worth the roughly $2,000 premium these systems command?

The short answer is this: AWD and 4WD help a vehicle accelerate in slippery conditions, but they don't aid with braking and only sometimes improve handling. That said, you shouldn't necessarily cross the feature off your shopping list.

The terms AWD and 4WD are often used interchangeably, but they operate differently and are found on different vehicles. The Edmunds Car Glossary defines the two as follows:

All-wheel drive: A drivetrain that employs a front, rear and center differential to provide power to all four wheels of a vehicle.

Four-wheel drive: A drivetrain that employs two differentials and a transfer case to provide power to all four wheels of a vehicle.

All-wheel drive is found on cars and crossovers such as the Subaru Impreza and Honda CR-V, while 4WD is reserved for trucks including the Chevrolet Silverado and truck-based SUVs such as the Toyota 4Runner.

The Textbook Cases

There are some cases when you should give AWD and 4WD serious consideration: for example, if you live near or spend time in places with unpaved dirt roads. Similarly, if you live in places where it rains or snows for many months out of the year, AWD or 4WD will help with traction and should be high on your list of must-have car options.

But for some people, the choice may not be that clear-cut. Here is a list of pros and cons to help you make a better decision.

Pros of AWD/4WD

Better acceleration: An AWD or 4WD vehicle can accelerate better than a two-wheel-drive vehicle in inclement weather. "The advantage provided by AWD is mainly in the acceleration, as the traction needs will be equally distributed among all four tires," says Cyrille Roget, a spokesperson for Michelin North America. On a car with front-wheel drive, "the need for traction will be transmitted only on two tires," adds Roget.

Helps with traction and towing: A 4WD truck's improved traction can help if you are towing from a wet, steep boat ramp, says Dan Edmunds, director of vehicle testing for Edmunds. Similarly, if you go camping off-road in dirt or in sandy areas, a vehicle with AWD or 4WD will reduce your chances of getting stuck. But you don't need these systems if towing on dry, paved roads and camping in developed spots are your thing, says Edmunds.

Improves dry handling: This benefit applies only to AWD vehicles with torque vectoring. The AWD version of the Acura TLX is one example. Acura's Super Handling All-Wheel Drive (SH-AWD) distributes torque to all four wheels, using a pair of electromagnetic clutches to freely regulate torque distribution between the rear wheels. This system is one of the rare cases in which AWD can help with cornering.

Added resale value: Your vehicle may be worth a bit more if you live in an area where trucks are popular, like Texas, or in a place with harsh winters, like Colorado. People are willing to pay a premium for vehicles with AWD and 4WD, says Richard Arca, associate director of vehicle valuations for Edmunds. If you look at the depreciation curve for these cars, value dips initially, but then the cars regain their value after a few years, Arca adds. But if you live in a place with milder winters, like Southern California, there will be less demand for AWD and 4WD vehicles, and buyers won't be as willing to pay for the feature.

Cons of AWD/4WD

Added cost: The cost of an AWD or 4WD system can range from $1,300 on a Honda CR-V to about $3,500 on a Ford F-150. You'll also have to factor in slightly more for gas because the vehicle's rated fuel economy will be slightly lower.

Lower fuel economy: The AWD and 4WD components weigh more and place a higher load on the engine. These factors will decrease fuel economy by about 1-2 mpg. It may not seem like much, but this is a 5-10 percent decrease in trucks (4-9 percent in cars and crossovers) and can add up to a couple hundred dollars in a year.

More maintenance: The differentials on AWD and 4WD vehicles require oil changes. And though the differential fluid doesn't need to be changed as often as the engine oil, it is an extra maintenance item to account for. These oil changes range from about $40 to $150. If something goes wrong with the differentials, they tend to cost more to repair than with a 2WD vehicle.

False sense of security: It is easy to be lured by an automaker's advertising and think that having AWD means you can drive in the snow or rain as easily as you would in dry conditions. But the truth is that AWD and 4WD help only with acceleration and traction. Braking distances and handling will be the same as with a 2WD vehicle.

Focus on Good Tires

Ultimately, your vehicle's tires can be more important than the number of wheels being driven. For example, the Audi S5 is an AWD car, but it's not a great idea to take it for a ski trip straight from the dealer's lot. That's because the S5 comes standard with summer tires that wouldn't do well in the cold.

Here's another way to think about it: What would perform better in the snow? A front-wheel-drive car with winter tires or an AWD car with all-season tires? Michelin tested this scenario in a study a few years ago. The FWD car with winter tires outperformed the AWD car in nearly every test. The AWD vehicle had the edge in acceleration, but when it came time to hit the brakes, its braking distance was significantly longer than the FWD car's. Of course, if the AWD vehicle had a full set of winter tires, it would be the hands-down winner, but it goes to show the importance of good tires.

Don't Buy a 10 Percent Car

People sometimes buy an AWD or 4WD vehicle for the occasional off-road outing or ski trip, while 90 percent of the time they'll be using the vehicle on paved roads. These drivers would be better served by renting a car for their ski trips. This route will save them money on the price of the car and in lower fuel costs.

Wherever you end up, make sure you take the time to weigh the pros and cons and find the right car for you.