The report, out today, ranks 10 non-folding treadmills, 25 folding ones, and 31 ellipticals.
Some come with such high-tech bells and whistles as MP3 docks, WiFi or USB connections that let you download your workout data onto a computer. Others offer a 'negative-incline' option, meaning you can run downhill as well as up or on the straight-and-level.
Author Jamie Hirsh, Consumer Reports' senior associate editor for health, tells buyers what questions to ask before making a selection, including: Will your elliptical smack your head into the ceiling? It could, if the path of the pedals is too high and the height of your ceiling is too low. You want to be fit, not unconscious.
Though both types of machine -- treadmill and elliptical -- can give you a workout as strenuous or as gentle as you want, there are important differences between the two. Treadmills, says Hirsh, are by far the more popular.
"I imagine it's because they've been out longer than ellipticals," she says. "And they're not very complex: Everyone walks and knows how to walk. There are many models and many price points."
The advantages of having a home machine of either type, she says, include "not having to worry about what you look like" when you exercise. You're spared the curious glances of fellow exercisers, which you'd have to deal with at a gym.
And you're spared their germs, too. Neither rain nor snow nor dark of night need interrupt your exercise routine. If all you want to do is walk, says Hirsh, you could do it indoors at a local mall. But running? "That's not an option. I tried it at my local mall and was stopped by security."
Consumer Reports divides its list of recommended treadmills into folding and non-folding, the former better suited to smaller homes, where they can be tucked out of the way in a closet or garage. The time and effort needed to fold and unfold them varies, depending on the model's weight and whether or not the unit comes equipped with an hydraulic lift.
Consumer Reports' highest-rated non-folding treadmill is the Precor 9.31, priced at $3,300. Its features include a chest-strap heart-rate monitor.
The category's best buy is the PaceMaster Platinum Pro VR, which sells for $2,000 and also comes with a chest-strap heart-rate monitor. In addition, the PaceMaster's bed can be inclined negatively, to simulate downhill running. This allows you to work different muscles.
Both models offer controls that let you shift quickly and easily from one speed or rate of incline to another. That's an important feature for anybody wanting to do interval training, says Stefan Aschan, a fitness coach and author of "The Alpine Weight Loss Secret," due out January 10. Interval training depends on the user being able to switch quickly between a fast and slow pace, a high and low level of intensity.
Aschan and Hirsh say anyone with weak or sensitive joints -- including persons who have had hip or knee replacement -- may be better off buying an elliptical machine, which typically subjects the body to less impact than does a treadmill. Before buying, take it for a test drive. Each model has its own characteristic elliptical path: some are long and flat, like a ski stroke; others short and more round, like a bicycle.