It is good but only against enemies that dont really move, against devil walker it is amazing, it is good against sepics prime, and fairly good against the cabal boss (although he still moves and bit and will move away before taking full damage usually), phogoth and the arcon priest tend to move a lot more so it is very good on them (unless you have someone stun locking them, but that is not the rocket launcher on its own), and it is just bad against omnigal, she just moves to dam much. The reason gjallarhorn is so much more popular is because it is a fire and forget rocket launch and it deals the highest amount of damage on a single target, whether or not they move, normally when i pull out my rocket launcher it is to kill a boss, not random enemies, i want my rockets to hit (missing one rocket when you only have 5 is a big loss), and i want it to hit fast and kill the enemy fast (i dont want to have to hope that the enemy decides to stand still). That is simply why i will always choose gjallarhorn over dragons breath.