Hydro boost is the hot setup. They put that on at the factory on those big huge buses and dump trucks and delivery trucks, it is extremely effective ( although I do like the electric pump backup on the larger units a bit better than the accumulator that comes on these smaller units, but these wil still stop fairly easily if the pump belt fails )
Just make sure you have GOOD friction material, get the semi metallics or ceramics uofront and the ambulance grade on the back and you wont have fade issues, and replace all teh hardware and make sure to grease the adjuster threads with syl-glide silicone brake grease and they will work. Mine work fine, but you MUST make regular jaunts in reverse with multiple stops to keep brake shoes in adjustment, and people have gotten spoiled and forgetten how. I have a nice hill in front of my house and as often as I can when theres no traffic, I'll let it roll backwards when leaving the house and hit the brakes to a stop about 10 times or so to keep the brakes adjusted up. It keeps me from having to crawl under.
Drum brakes are actually very efficient, and the add on kits are generaly less efficient , the only way you would make them better with disc would be to get an f450/ superduty axle and swap the whole thing on there brakes and all, but you are going to wind up with a lower gear ratio and if I'm not mistaken, 10 lug wheels