A lot of people i know hated Guild Wars, I myself never played it, the only thing semi-appealing is not paying a monthly fee, but i also heard they stick ya with a fee if you want to purchase additional classes n' such. I have played WoW, it's a decent game and i've played plenty of MMORPG's. It's widely popular (they even had to stop manufacturing cd's shortly after release because there were too many people playing and the servers couldn't handle the stress). Latency was a huge issue at release but all/most of those problems have been resolved.
Wow has several features that make it easy for all players. The interface is simple, and based on all other MMORPG's ive played, i think it's the easiest to level up. There is no experience debt, infact the only penalty of dying is your armor/weapon's durability goes down. All in all it costs you money to die and time of course(to walk back to your corpse). There are, of course, several server types to suit your playing style, whether you want to play PvP, Normal, or Roleplaying server. Don't fret, you can still PvP in the normal servers, it is however, totally optional, as opposed to always being flaged in PvP. I myself favor the PvP servers, it's not totally chaotic though, many of the new areas don't auto flag you, so you can get to level 15 or so without seeing any opposing faction attacking you.
There are a couple ways you get around the World of Warcraft, no pun intended =) Walking is the most basic option, there are ships that travel between continents, and at level 40 you're allowed to purchase a mount, and an even faster one at 60. Lastly, the Warlock class in the game can summon players with the help of 2 other friends. Give it a try, it comes with a free month anyways,
www.worldofwarcraft.com. Hopefully someone will shed some light on Guild Wars.