Reasons why I love Guild Wars:
A story driven game with cutscenes.
You can "beat" it in a reasonable amount of time (ie. complete the story)
It takes very little time to hit max level and from there on its all max level content.
PvP cannot be beat by any other game I have played.
Little to no grind required.
Tons of ingame jokes and lots of funny dialogue.
You pay once and you're done.
You always have henchmen with are 9/10 times better than joining a public group.
IF you get Nightfall you get heroes, which are fully customizable and controllable henchmen.
No other players to annoy or kill you while you're out doing missions or quests, all parties are formed in towns.
The skill setup itself is fantastic. Pick 8 skills and thats all you have to work with, so choosing a successful combination of 8 skills is always fun.
You can change your attributes and secondary class at will, so no need to ever reroll or buy an item that lets you reroll.
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Some comments.
While no grind is required to do anything in the game, you do have the option if you wish it. There are now "titles" that rarely actually do anything other than display underneath your character's name. Those typically include grind.
You can get max armor and max weapons for very cheap and no grind is required to obtain those. However, there is "prestige" armor that cost a hell of a lot more yet offers no benefit over other max armor or weapons, it just has a different skin.
I have also played City of Heroes and WoW, and I agree, Guild Wars cannot compare to either of those games, its just so much better
The single advantage those games have and its actually pretty major IMO, is the inclusion of a jump key. You cannot jump in Guild Wars unless it is via emote.
I've been playing Guild Wars since the betas myself, and have logged way too many hours, but I still play almost daily, so hit me up if you grab the game.