What you really end up with is access to the first part of the world, then you'll have to pay to unlock things such as classes, skills and even missions - you know, the whole point to the game? Better yet, if you pay the $15 a month subscription fee, you still end up having to pay money for little things like, oh, healing potions. Hell, they even have NPC's you have to hire by the hour just so you can beat a mission you had to pay for to begin with. This entire game really centers around the shop which, surprisingly enough, costs money to use.
In the end it will probably be cheaper for a serious player to stick to WoW.
For a more in-depth game review, check out MMOCrunch.