It's would be noteworthy, that the educational and free versions of RenderMan (the next release) isn't available yet.
As always, it'll be Real Soon Now.
It's also noteworthy (unless it's because I've never done any commercial grade graphics) that they don't have system requirements or anything even close to that. So if one just plans to "play with it" we have no idea if it's x86, IA64, ARM, iThingy (whichever variation) or a bloody Atari (or even a bank of them).