Brand
One way to compare treadmills is by brand. There are a number of different treadmill brands, and each has its own loyal following. Nordic Track, True, Life Fitness, ProForm, Landice, and Reebok are just a few of the popular brands of treadmill.

When looking at a treadmill by brand, be sure to read consumer reviews and reports on them. Some treadmill brands are notorious for mechanical problems, or bad warranties, or poor quality. In some cases, you'll also find that you are paying more for the name than for a quality product or for features. Make sure you try the treadmills out, and ask the salespeople which brands are the best and which have the most problems.

Price
Many people compare treadmills by price. Often, two treadmills will be priced similarly but come with very different features. For example, the Reebok 9500 treadmill comes with a built-in entertainment center and over 35 different workout programs; but for $1,000 more, the HRC 525 features just 4 different workouts and no entertainment center at all. Make sure you are getting as much as you can without compromising quality.

How much you spend will also depend on what you need. For example, if you only want a treadmill for walking occasionally when the weather is bad outside, there's no need to spend $4,000 on a treadmill with a commercial grade motor that reaches speeds of up to 12 mph. At the same time, if you plan on running on your treadmill at high speeds every day, you won't be happy buying an entry-level treadmill that is uncomfortable and noisy. For that reason, it's important to compare treadmills by price based on your needs.

Features
Obviously, most people will want their dollar to go far, so they want a treadmill that has as many features as their budget will allow. When comparing treadmills by features, make sure you are looking at things you will actually use. For example, Nordic Track's Viewpoint Series has a number of features specifically for people who want to watch TV and listen to music while exercising. However, these are not features you'll want to spend extra money on if you prefer to read while on the treadmill.

You will also want to look at things like pre-programmed workouts, like weight loss or interval training, and compare treadmills that way.

Warranty
When comparing treadmills, make sure you don't forget to look at the type of warranty they offer. For example, some treadmills offer 3-2-1 warranties (3 years motor, 2 years parts, 1 year labor) while others offer lifetime warranties on parts, and everything in between. Make sure you choose a treadmill with a good warranty for the motor, parts, and labor when comparison shopping.

Comparisons are important to make when shopping for a treadmill. Decide which factors are important to you, and then compare different treadmills by price, brand name, and features before buying.