Just tested out my Asus g55vw-ds71. It's funny, when i started out in the tutorial area, the sliders being set to best performance made the game play beautifully at full 1920/1080 resolution. When it is set to best appearance you will notice some more fuller and sharper images but not that much that will make you go wow.
However the game on either slider looks beautiful and ultimately the only thing that really changed the feel was the FXAA which made the game look rounder. Tbh, I prefer having that off because of personal preference.
I tested out max settings in wvw and honestly, you will experience a few camera hiccups but in the heat of battle the laptop actually kept the frames and the hiccups will not hinder your 1v1's. Most of the hiccups were when the character wasn't moving and i was just doing some panning and rotation of the camera, could be lag. Honestly, guildwars 2 looks beautiful on this machine and runs like a dream. You honestly only have to turn down a few settings if you want absolute flawless frames, such as turning of fxaa, shadows, and maybe bringing down terrian textures by a notch but you really won't care once you're playing it. If anyone is thinking of getting this laptop, its worth the investment and will suit gw2 just fine.
Update: My review of the asus g55 isn't that clear. Just spent 5 hours playing on it. Long story short, yes it will play gw2 on max at 1080p resolution and have no hiccups when a group of 20-30 people are on screen and using everything they got. WvW and a few dynamic events made this apparent.
Gonna test out my Asusg55vw-ds71 this weekend and see how much i can max out gw2 in WvWvW. I'll let you prospecting asus g55 users some details about what i have to tune down. My goal is to get flawless frames at the highest setting possible. Push the 660m to its limit.