Marc, Thanks for your opinions. I currently have my code using echo and will probably keep it as such.
To answer your question, "Why XML", the answer is because I am feeding an XMLHttpRequest and the JavaScript code I'm using expects XML input. I could send JSON data, that would be more efficient, but I decided to stick with XML as it is more ubiquitous and will allow me to use RPC to fetch this data in the future if I so require. -Josh
