Most shocks are made by Monroe, including Rancho. Bilstein and Fox make their own shocks. I've blown up more Rancho shocks than I care to count also. I snapped several shafts, tore mounts out, ripped the valves out the top, and the ride flat out sucked...
After switching to Bilstein shocks, I've never had a problem other than the occasional leaking seal.
With a diesel Bronco I'd weigh all 4 corners of your rig, and call Lee at
www.raceshock.com and talk to him about what shock you'll need. Bilsteins can be bought in specific valving, and if bought from Lee (or any other competent dealer) they can be revalved fairly simply if your not satisfied with the ride. I bought 2 of my 7100's and had 2 used shocks rebuilt by him and couldn't be happier his service or with the ride of my Bronco. I've recieved compliments from many other Bronco owners on the quality of the ride.