I was wondering why the development team behind Fable 2 chose XSI over Maya?

I am a 3D artist and my personal weapon of choice is Maya. I must admit after looking at what the newest XSI incarnation is offering I must admit I am getting tempted to shift over to XSI from Maya however I have used Maya since the quite quaint 6.0 version and am now quite comfortable with it, however if Maya 2009 offers nothing new other than some simple bug fixes (like Maya 8.0 to 2008 has nothing new to offer really and doesn't warrant the huge upgrade costs) I will be shifting over to the new XSI as my new preferred weapon of choice.