I haven't gotten mine installed yet because still dealing with the front end issues, however, I already popped for an ECI part. Namely because they were very helpful with my 1-ton and I think the provided me with a very good solution. The guys I talked to up there were very patient and knowledgeable.
I got a power boosted 1 1/8ths master - and its a small booster (7"). They told me that with the load of the truck it won't be like my car, but it will be better than manual brakes. I am thinking it will be good because I have these (as yet untried) kevlar brake shoes and the truck is about 1600 lbs lighter than it was originally.
