If it's purely a choice between XML and JSON, I'd agree that XML is a bit better. I'd prefer to use neither. Most of these UI layout formats are essentially co

If it's purely a choice between XML and JSON, I'd agree that XML is a bit better. I'd prefer to use neither. Most of these UI layout formats are essentially complex domain specific languages, paired with IDE support. I don't see any particular need to base them on XML, which was intended for marking up documents.