Hey old friend
You might remember a year or so back that I was testing out Maya. Well after a lot of testing I went with XSI. I do not regret it one bit.
The modelling will blow you away. I have yet seen a program that runs so smooth. This thing is a piece of art. I always will have a soft spot for Cinema 4d. I see with r9 that they finally got n-gons! Nice job. However stepping into XSI is the closest I have come to 3d nirvana.
Max, Maya and XSI all have mental ray. However in XSI it does not feel like a add-on like the other two. It is totally integrated. While it is harder to learn I feel it is not as hard to learn as say in Maya. Quality wise there is no doubt it is a step above Cinema. That is not a insult at all. Cinema has a very good renderer. It is very easy to use. However the length you can take mental ray is so extensive. You mention sketch and toon. I have seen toon shaders on XSI that blow me away.
Take a look at this article
Node based shader tree. I think you will have a ball with it. You get that 5 dvd training set. I am pretty sure that would set you right on the way to beautiful stills.
Bottom line is Flingster that IMO XSI is the best “3d artist” product on the market. Obviously there is no better time to jump in.
I am not going to knock Cinema. It is a great product. I got a lot of respect for it. I just think XSI brings the artist tools to another level.
Shame we could not work on that little film we had in mind because I was testing out software. If you do get XSI then hit me up sometime