I've seen videos of AoC gameplay, and it actually makes it feel like you're moving somehwere when you walk. In WoW, its kind of feels like you're moving slow as hell, or the world around you is unrealistically HUGE. Until you get a mount...then its like....
WEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE
I've been playing since beta, and ill tell you that if you enjoyed the trial, theres no reason why you wouldn't love the whole darn game. Just remember that you can back out at any time, and FFS, MAKE SURE YOU ENJOY IT! If you don't, just stop playing. I got hooked for the longest time trying to get from 26 to 60, and it was a rather unhealthy phase I went through. It was only after I hit 60 and was apparently a noob that I managed to stop.
Sorry if that scared you. Anyways, for all the complaints about grind, it really isnt that bad, its more the quests being same-y that might bug you, but at the same time, quests give big chunks of xp, so if you can get through those, leveling will be a breeze. The whole "boring quests" thing changes in the first expansion up until 80 though.