Erianna's Vow is probably the most useful with its strong damage, plentiful ammo, and innate Anti-Barrier rounds Devil's Ruin would be my second pick, but personal favorite. The "Laser" does shocking amounts of damage and has innate Unstoppable properties, which are useful. Also has a bunch of fun build potential Leviathan's Breath is a slow, Heavy Weapon bow with Unstoppable Rounds. Not terribly useful in my eyes. Not very good compared to other more used Heavy Exotics imo Bastion is one the best PvP Fusion Rifles right now. Fires a powerful burst of shots, but falls off faster than other Fusions. Personally relate it to the Lord of Wolves. Don't think it brings too much to the table PvE wise Symmetry is gimmicky, but can be good if you're accurate. Not much utility here, but can be fun Definitely recommend checking out some videos, but I'd personally lean towards Erianna's Vow or Devil's Ruin