As some one who has all three exotics here is my opinion: Thorn for PvP, Hawkmoon for PvE, and Last Word for Gunslingers. Thorn is heavily underrated because of it's insanely slow reload which makes it horrible in PvE; but in PvP it's two headshots for a kill plus the DoT from Mark of the Devourer keeps players from recovering and let's you see where they are through walls (damage indicators are visible and show you their location.) Hawkmoon is a beast; high impact and range, 13 shots to the magazine, and 3 shots out of each mag do an extra damage on top of that; for raw damage per mag it can't be beat. The Last Word sits between Hawkmoon and Thorn for many; it has high impact and is fully automatic with a high fire rate, but it severely lacks in range and only has 8 shots to a mag. If you get good at getting hip-fire precision shots every one gives you extra precision damage that's close to the damage bonus on the random shots in Hawkmoon. Where Last Word really shines is in the hands of a Gunslinger (it is the Golden Gun afterall...) with Chain of Woe and Gunslinger's Trance active Last Words insanely high fire rate combined with buffed stability and reload time gives it the highest damage per second out of any hand cannon I've used regardless of it's lower damage per mag compared to Hawkmoon. I hope that helps.