Q: Which is better, Max, Maya or XSI?
A: They all can do pretty much the same things and they all have not so perfect sides to them, there are trials and learning editions, try them, find what suits you best and make a decision. It doesn't stop with those three programs, there is Lightwave, Cinema 4D and Blender (which is taking big steps and is free).
Yeah yeah, I know the Maya icon is old but its my favorite <3.
NOTE: Autodesk has announced that early 2016 Softimage will be discontinued. Softimage version 2015 will be the final release.