Elliptical trainers are ideal if you're looking for a total body workout that burns maximum amount of calories in the least amount of time.

They also provide a very low impact workout which makes them great for any exerciser including those with knee problems or older athletes who don't want the impact on their joints

If you're buying an elliptical machine here are the key factors to consider before buying in order to get the most value for your money:

1) Price

Ellipticals range in price from $300 to $3000. It's up to you what you pay. Just keep in mind that price reflects quality - you generally get what you pay for. That $300 department store elliptical may seem like a bargain until the 3rd week when it develops a high pitched squeaking sound that drowns out the TV (don't laugh, it happened to me.)

Economy priced elliptical trainers are simply not as well built as higher quality $900+ units. Cheap ellipticals can end up costing you in repairs, injury and an overall less effective workout with less calories burned.

If you're planning on using your elliptical regularly, spend a bit more and invest in one that will last you.

2) Forward and Reverse motions

The ability to move in a forward or reverse motion adds variety and challenge to your workout. This also reduces your risk of repetitive use injuries common with some treadmill and stair climber users. Most ellipticals have this option but it's always a good idea to make sure it's offered on the unit you want.

3) Adjustable Resistance

Quality eliptical trainers will have a range of resistance levels. Look for a unit that makes resistance changes simple (i.e. one-touch resistance adjustment) so that interval training sessions can be easily incorporated into your workout

4) Upper Body Arm Bars

While you really don't need these for an effective workout, many people prefer them. They do help to provide resistance training and toning for your upper body.

However make sure you don't have to lean over while using them which can diminish the effectiveness of your workout (this can happen on many of the cheaper models).

5) Weight Capacity

The user weight capacity indicates the quality of the elliptical. High quality machines will have higher user weight capacities. A higher user weight capacity (i.e. 300+ pounds) generally means a much more stable elliptical. This is essential if you want to pick up your pace during your workout.

6) Warranty

While warranties range for different elliptical trainers, choose a machine with at least a one year parts warranty - preferably longer.

The length of the warranty is another indicator of the quality of parts used to build the machine. A longer warranty tends to indicate a better-built machine.

(However I'm not talking here about the 'extended coverage' warranty you have to buy with some cheaper brands. If you have to pay for extended coverage that may not be a good sign.)

7) Display panel

While there are a range of different options here, it really depends on you. Do you want to see calories burned, speed, time, distance, incline? Do you want to see them all simultaneously?

One good rule of thumb here is to make sure the console is well lit so you can read it while you exercise.

Finally remember to consider everyone who will be using the elliptical, their weight capacity, workout preferences and fitness goals. By knowing these facts, you're way ahead of most buyers and well prepared to choose the best elliptical trainer for you.