Having played both Guild Wars and WoW extensively, I can honestly say without any biased opinion that the quality of content that is dished out for WoW is just..better. I mean, it just is. Probably due to the fact that you pay for it.
Blizzard makes an estimated 150, 000, 000 dollars a month from subs alone. That's not including transfers, pets in the store, initial purchase cost, just subscriptions. Lot of cash. They have a HUGE team that is constantly developing content, but again, you pay for that quality of content for 15 dollars a month.
It still kinda pales to the quality of the content you got for 30 dollars flat with no monthly fee

Besides, for a new player, how much of the actual content he'll ever see? Most epic stuff that happens
before level 85 is obsolete. You start your quest chain to save the world from some primordial evil, and before you know it you outleveled the area and are in the second expansion zone tackling the other primordial evil which you'll also leave to it's plans before the end cause you reached 85 where all the real content is

At least with GW, nearly every is actual non obsolete content

And you can get a bundle wit the 3 games for very cheap. It cost me two months of WoW subscription only and I got months and months of content to play with whereas with WoW you have to buy the game AND pay every month after the first.