Most machines have settings that let you increase resistance, so your legs have to work harder to get the pedals around. You can also adjust the incline, so you can go from flat running to steep climbing in the push of a button.You’ll find elliptical trainers at practically every gym and health club. If you like them enough and have room in your home, you might even consider a personal model. Until recently, it was tough to find a quality home-version elliptical trainer at a reasonable price. But these days, options abound. Here are three models we’ve put to the test and would recommend.   ProForm 900 Best Value at $500This bargain-price machine is also the most compact of the bunch, so it’s a great choice for those with limited cash and space budgets. It runs on four D batteries, so you can put it anywhere. Moveable arms let you work your arms along with your legs to rev your calorie burn. Unlike the other two models, it does not have an incline feature, however, so your workouts are somewhat limited. Some testers found the foot pedals a little too bouncy. For buying information, call (800) 380-3868.   NordicTrack CXT 990 Most Features, priced at $1,000Provides great versatility with both incline and resistance features to make your workouts easier or harder. It also offers the most pre-set workout programs of all the models. The moveable arms allow you to pump your arms along with your legs to burn more fat with each workout. The one downside: Many of our testers felt that the footpads were placed too wide apart to work out comfortably (always try machines before you buy!). For more buying information, call (800) 234-5031.   Precor EFX 5.17 Highest Quality, priced at $2,500 If you have the money and you’re looking to invest in a machine that’ll last a lifetime, this is the one. It is the smoothest and most stable, and will likely hold up the longest. The control panel is very simple and easy to use. Parents of young children will appreciate the childproof safety feature that lets you lock the wheel, so little fingers can’t get into working parts when you’re not around. Unlike the other models, the Precor does not have moveable arms for an upper body workout, nor does it have any pre-set workout programs. For buying information, call (800) 786-8404.