I don't use thorn because I think it's a horrible gun. However, thorn is a deadly weapon in the hand of person who knows how to use it. Isn't this the point of PvP. Use the best weapon that give you the highest chance of success? "I'm going into a competitive PvP match and I'm going to use the worst gun possible" say no one ever! With that said, different guns used by different players can have positive or negative results. Some player can be really awesome with one of the worst gun.