Well I've played both Guildwars and WoW, I had all three expansions for Guildwars actually, and storywise, it's absolutely brilliant, it's just how silly things can get on it, I mean, I saved up for full FoW armour (Like 75 Platinum a piece AND Ecto's...) on my Warrior, Necro and Dervish, and was like "Wow this costs alot but shit yeah I look awesome", and I dyed it all black, which they were 6 Platinum a go..., and then made a 55 Monk cause they're brilliant, well, they were till they got nerfed...
But now you think about it, the prices of items were terrible, you could find a perfect sword with Req 9 and 11-21 damage (Was it that ?), with like +20% Armour Pen and whatever else perfect things gave you... and it was 5 Platinum, however, if you want it to do the exact same thing, but look better (i.e Icy Dragon Sword), you've gotta pay like 100 Platinum and up ! I don't see why o.O
Something else that let it down for me, was the fact that you could only get to level 20, and do it in less than a day, you know when you get ascended in the desert, where you gotta kill your clone, yeah... if you do it in less thana minute (Which I did), you get bonus exp, and I levelled from 13-20 from that one fight... kinda TOO easy if you ask me, I think the game would benefit more from more PvE and higher levels, which Guildwars 2 promises to have, and it DOES look promising...