Treadmills are stepping up in the world with options like built-in TVs and fans. But defects in some of those we tested show that quality control remains an issue.

The 18 models cost $1,000 to $3,500, a large enough outlay to make an in-store tryout essential, and four models are CR Best Buys (subscribers can get full information in our Ratings).

High prices notwithstanding, manufacturing defects continue to show up:

Even if a faulty treadmill is fixed under warranty, any repair--especially one needed right out of the box--is a hassle.

Check your space. A nonfolding treadmill takes up as much floor space as a small couch, a folding model about half that when closed. One folding model is especially suited for cramped quarters--it's about 6 square feet when folded. But its deck might be too small for all-out running.

Consider your workout. If walking is your exercise, any of the treadmills we tested should be fine. If you’d rather run, choose either a nonfolding (and more stable) model or a high-rated model scoring excellent in exercise range.

Consider the features. An LCD TV is part of one treadmill's control panel. Several models have cooling fans built into the console, but they’re not as effective as a floor fan.