From what I've seen so far, in Cantha you have to 'figure it out' a lot faster, else you die. In Tyria you have a happy little noob-land (pre-searing) to actually guide you through the basics of the game. Shing Jea Island on Cantha is kind of like that, as they do some of the same instructional things, but it's nowhere near as beginner friendly IMO, and it's not as good at letting you set your own pace. Now on the other hand, Cantha is "where it's at" right now, so you may want to start off there... basically I'd just keep in mind whatever you think your learning curve is and base your decision from that. Remember, at a certain point you can take your characters from Cantha to Tyria and from Tyria to Cantha, provided you have both a Factions and Prophecies access key on your account.