XUL and PHP - what's your opinion?

I keep hearing about XUL, and I was wondering what the opinion of the masses was on this subject for an internal application where the browser is pre-determined. From my point of view I, having only read about it and not used it, is that XUL would make your applications look more like a desktop application. Some of the widgets they provide come in handy, like tables that can sort themselves instead of using AJAX/another page hit. The down sides that I see is there would be a 99.999% chance of a learning curve for any new developers that come into the company. Also, I'm not sure if XUL would cause extra programming overhead than regular HTML/JS. -- Ray Hauge Programmer/Systems Administrator American Student Loan Services www.americanstudentloan.com 1.800.575.1099