I don't think there are really that many differences between the data centers. Like people say, Crystal has Mateus and Balmung for roleplaying, and Aether may have a larger base going after raid content, but largely I feel they're all practically the same.

I don't plan to ever move my main from Excalibur because this server is largely very chill. It's good to see people shooting the shit every so often, though I'd prefer it to happen far more often than it does. Many people playing MMOs these days don't care about the communication aspects promoted.