For me there is absolutely no comparison. I enjoy World of Warcraft PVP, and League of Legends, but World of Warcraft has so much more crap going on. Like to even think about being good with your character in WoW it could take months of playing him over and over and learning all kinds of macros and keybinds, whereas most players can hop into LoL and have a fair amount of success because of how simple the game is.
What is YOUR opinion? And why?