While I love this treadmill while it's working, it seems to be more problematic than helpful. I adore the functions, ease of use and "feel" of the platform but the tightening mechanism that NordicTrac has chosen to use makes the product "cheap" after only a few miles. Performance I was very displeased with the perfomance as the tightening mechanism is plastic with a couple of metal inserts so, as the belt gives and begins slipping, tightening is required and on the plastic, it eventually gives and has to be replaced. We replaced the end twice and in short intervals so I was a bit unhappy. I sold this treadmill to a man that did nothing but walk as running became dangerous when the belt began skipping/slipping. Comfort When this product was tight and stable, it was one of the most comfortable products I have run upon but the slipping took that away. I began to be fearful of a slip and then fall. Ease of Use This is an easy product to use until you have to replace the bottom portion. Durability Same problem as stated earlier. Cheaply made tightening mechanism. Design Love the way it is designed. It's easy to use and friendly by design. I wish it would hold up better.