I have purchased, used, and am very happy with my Comfygo auto recline IQ9000 Plus chair. I have used it on a variety of surfaces and it works well on all of them. I toured around the Washington State Fairgrounds for 5 hours . The chair was very comfortable to ride in and used only 80 % of the first battery. The chair maneuvers well, stops and starts on command and the joystick is easy to use and responsive. Overall the chair is much more sophisticated than I expected. I recommend this chair and would purchase it again.