Two words. Buy, now.
This game has a maximum character level of 20, disappointing? Not at all. This is not a game where your status is decided by your level, and you won't be spending hours and hours training to reach your next level, especially when there are literally hundreds of quests to go at alone, or in a party, for experience. One thing I found fun in this game was co-operative missions, giving you the chance to work in teams of up to 8 players to unveil major breakthroughs in the storyline, and most of all, make friends.
Once you reach level 20 there is one thing to say, PvP. The PvP in Guild Wars is unrivalled, and you are given the choice to make a PvP only character which starts at level 20 and lets you PvP wihtout having to go through the game levelling up.
Another good thing is that when exploring the map you can't come across other players, other players are only visible in Towns or Outposts, which solves many problems common in other games, such as KSing or Kill Stealing.