i have them on our automatic and as long as they are installed right they work great, i recommend having them installed by a commercial over head
door company that has experince with them. The only problem I have had is that the belt will slip and the
door will only go half way up which doesnt really please the customer to much but I have the rubber belts on mine but I would almost consider going with the chain and sproket which is cheaper and less likely to slip.
They do a good job holding the heat in and the panels are doubled up and clear with air gap in between (much like a home window) which actually seems to help heat the bay when the sun hits it...