PvP and PvE are different skill sets. Ive done both and enjoyed both. I like PvP more personally.
You can be good and bad at both. People who prefer one and say that the other takes no skill are wrong. PvE is a scripted fight, but its not going to make any mistakes. PvP you dont always no what to expect when fighting a person, but people also make mistakes.
If I had to choose I might say that at the highest levels of competition PvP might require more skill, but the difficulty of PvP is relative.