I've now been playing this game for close to 2 years, since its release nearly. I've played nearly every night for a few hours, without fail. Graphically, this 2 year old game is still amazing. I still discovers things ingame that I hadn't noticed before and it blows your mind at how beautifull they look.
Playability and lifespan is 100%. There is always something new to complete, unlock or achieve. 100s of quests, lots of professions, plenty of armor types, lots of skills etc etc..
I have never had any major lag issues when playing (unlike competiting MMOs you can buy). The game uses an instance system, where locations outside of towns and cities are unique to you. This may not sound like a true MMO, but it works really well and you can let humans join you during these instances or take henches.
Missions are challenging and quests fun to complete. You also have titles to earn and max, to show how good a player you are.
The max level cap may be only 20, but it incourages people to aim more on skill then "how good you look"!
I can't fault this game, except for the typical immature players you can encounter in MMOs. But that is unavoidable, and guildwars offers the choice to do everything with AI characters.
You dont have to play with other people if you dont want to!!!!
Earning gold and buying weapons and armor is a doddle and you still feel great wearing and using them. There is also a highly active community for GuildWars which constantly asks for changes which Anet do impliment at times.
If you are looking to play an online game, then I would highly recommend this game and its other independant games and expansions.
Prophercies is a longer game and takes time and effort.
Factions is faster and easier if you want earn stuff faster.
Nightfall is almost a happy medium of the two.