Well, not ALL of the team is building levels in MAX. Im building mine in MAYA and then packing them up for MAX. Unless of course twentyseven gets really generous and decides to make an exporter for Maya. But in all honesty there are so many exporters, you could probably build the level in any 3d tool you find to your liking. That would probably include MAX, MAYA, or XSi. I dont recommend milkshape, unless of course you are making a level that consists of 3 boxes.
Here is a look at what crenshaw looked like when I first drug it kicking and screaming from Radiant to Maya.
www.s8s.info/crenshaw_maya7.jpg