I can tell you two HUGE advantages that Maya has over Max... and if i'm wrong PLEASE correct me (it's been quite a while since i've used Max so i'm going on what i knew of it and what i'm still told about it. )

The biggest advantage Maya has is MEL. EVERYTHING is scriptable... even to the point of OS level. We click a button and it launches our Unreal engine editor or our game right out, while getting the newest versions from our source control DB. The tools we've developed with MEL are damn near incredible. Any modeling/texturing/animation tool that Maya lacks, our tools programers whip up in a day. I can ask for anything and by the end of the day i have it. Great stuff.

The second comes in the animation field. From what i'm told and from what i remember, Max is really weak on the animation side. ... Does it still not have IK? When i was choosing packages in college, that was the huge turnoff... animation with no IK?! HA! I went with Softimage (which is surprisingly lacking mention in this thread... XSI at least). In fact, ILM still uses softimage for animation.

I'm not trying to knock Max, it certainly has it's place. But all the people i've seen in the company move from Max to Maya have wondered how they got along without Maya for so long. So i'm not so sure it's package loyalty that's driving those folks who wouldn't wanna work in a company without Maya, some people just can't stand using Max =].

I for one wish Softimage hadn't dropped the ball with the insane delay with XSI.... XSI is damn amazing, and even more scriptable than Maya... you can use VB or Javascript in it for criminy sakes.