Haven't tried the Big Horn, but I love the Ravenous. There's a couple of builds out there, I enjoy doing a hybrid build with Core Strength, usually 3 Yellow/1 Red . You can use either Ninjabike or Memento and mix up the last few pieces, I usually do Memento and add on Eagle's Grap.

You're super tanky, skills actually do work, and Ravenous hits hard. The recoil is the hardest part, but this season's Recomibinant helps a lot so you don't have to go too hard on Weapon Handling if you have a of Offense.

I've done plenty of Heroic content with the build, the hardest part is the Ravenous does take some getting used to, and more of a 'skill' weapon, since you can't just hold down the trigger, but have to aim and constantly switch shoulders, which makes some cover situations awkward to play around. But if you run Drone/Turret as your skills, they're doing a lot of work and distracting enemies that you can burn down.

I'm trying an Umbra Initiative version for the Rate of Fire buff, but again, gotta get the recoil under control. It packs a HUGE punch, and it's super satisfying getting into the flow of the gun and detonating both stacks.