Invective is super solid with a cool weapon model. Bad Juju and Thorn both kinda suck right now but they look incredible and are slated for buffs eventually.

Invective I have all three you're being offered BTW Bad Juju's string of curses is only good against low level enemies/patrols Thorn, I have legendary hand cannons better than that

Vex Mythoclast

I'm doing the bad juju one.

Invective

Bad juju is a bitch to level up. But string of curses eats all the enemies. Just hold your trigger and aim head level(ish)

The invective is the easiest of the three bounties to do and out of all three I use the invective the most. Its great for PvE. The other two I've only pulled out a couple of times to mess around with when I was bored.

Honesty I haven't played around with them too much because I have 9 exotic weapons, but invective is strong at the moment but is getting nerfed along with all shotguns. bad juju and thorn are getting reworked/buffed in the future, but thorn is decent and bad juju is pretty much garbage right now (but I haven't unlocked string of curses yet, it might be better but I can't see it out shining thorn or invective)

My answer will be a little bias considering I care very little for shotguns, so Invective is going to be out of the question for me, sorry. But if you like shotguns, that is probably the best choice out of those three. Anyway, both Bad Juju or the Thorn aren't very good weapons. The Thorn is at LEAST okay with some of its upgrades later on, but it's still quite underwhelming. Bad Juju is just bad all around. Even with it's later upgrades, the weapon is only good for sweeping out the mobs. Still, both of these weapons are going to be getting a buff with the upcoming patch. But me personally, and just to be safe, I'd go with the Thorn.