No $700 treadmill is going to be a strong model. There are simply too many corners that must be cut in order to get the retail price this low.
If you are just a walker, this should be a fine model for you but the component quality is too low to be much more. Some serious shortcomings in major part areas are very evident with this machine. You should do fine with this treadmill if you are a light walker and don't use it too heavily but if you jog, run, or breathe heavily on it, you will break it! You are much better off putting a couple hundred with it and get one of the better HealthRider models.