Overhead door tech here. Chamberlain- which is also Lift master is the best operator brand on the market. Stick with a trolley belt drive. The belt drives have a little spring that helps tension the belt properly whereas the chain drive models are tensioned and then fixed in place by locking two nuts. I've seen it several times where the chain was Installed to tight and it sheared the drive sprocket off. Chances are it ( or any other brand for that matter) won't last you for life but you should be able to get 20+ years of service out of it which is pretty good. (Edited for speeling mistakes)