I really like my Jacobs. I had the dealer insall it a few months after I bought the truck. We pull an 18K fiver all over western USA, and it really makes a difference. I went with the Jacobs for warranty purposes. It is vacuum activated. If my truck was not under warranty at the time, I would have looked hard at PacBrake, or BD Brake. They work with compressed air, so I would have the benefit of an onboard air compressor for tires and such.
Good luck..... Steve
Jacobs uses a mounted vaccum pump that is very expensive to replace with a much longer serpintine belt.
JIM
Be prepared for a lot of interest in your truck after you install it (at least mine hisses like a dragon when engaged). I have all kinds of folks come tell me 1- my air brakes sound cool, 2- My tires have an awful leak, or just want to know what's wrong with my truck.