Hey, well I have 80 Dungeoneering and I'm maxed melee and I do the occasional PKing, Boss Hunting and PvM I boguht the Chaotic Longsword because it's in between the Rapier and Maul. Rapier is good for Slayer, Training, Low Defence-Mid Defence Monsters/Enemies. The Rapier, I guess you could say is a Whip with more power and strength bonus. Apparently it also shines at Bandos ;) Longsword is good for High Defence Monsters/Enemies (Tanks in PvP/PvM), High Levelled Bosses that need extra accuracy. The Longsword does just that, Accuracy with a load of strength. This sword is 1 speed shorter than the Rapier. Good Luck chosing!