The story portion of this game is where the majority of the focus went into when they developed it. There are 8 class story lines that each are fairly well written, and even though pretty much everything turns out the same at the end there are some small divergences that can be made within your story for titles or alignment that really have no impact on the game world outside of your story.
As for whether it's worth it, the game is free to play so the only cost is the time and hdd space to download and install the game. Free is usually worth it.
The F2P restrictions are pretty ludicrous for the lowest level of it, but at preferred status the game is fairly playable. You'll still have restrictions and it'll take you a little longer to go long distances than subscribers, but you won't be crippled.