It's different in that it uses the CPU instead of only a very narrow set of one company's GPU's.
It's different in that it's fully multithreaded (so, YAY multithreaded rendering in AE...kinda).
It's different in that it doesn't throw errors as often (much less likely to run out of RAM than GPU memory)..
Otherwise it's pretty similar. It's not there to do big 3d things. It's just there for quick 3d text/logos when you don't want to take the time to do things in a full 3d app or you want to use AE's animation tools.
I mean, I made a helix using AE's text animators and the C4D renderer. It was pretty fun.