when it comes to a quick fast projects i use max, easy and fair rendering time, but it crashes alot, xsi is very strong stable software, modeling and animation are amazing, will take time to learn but once you learn it, will give the power to create or animate anything.
par
Imad Mesbahi , 3D Artist and Motion + Graphic Designer , Freelance
i use the both Softwares but i use C4d frequently because the type of my work (Motion Graphics) and i use3Ds Max for the Complex modeling like Characters, Particles and other stuff..
I use Blender3D and Vue, also used3D studio max and Lightwave in the past.
Why Blender, A couple of years ago I had a licence issue with my Software, the moved to blender and fell in love with it. I believe blender is the best modeling tool and is olso best in UV Mapping.
For Modeling =3D Studio Max & ZBrush
For Animation = MAYA & CINEMA4D
For Rendering = VRay & Mental Ray
You can use all of them to finalize your project