Raytrace 3D never worked with AMD cards. CUDA is indeed a proprietary nVidia thing, but even then the Raytrace 3D stuff is a deprecated feature not worth hanging on, even more so on a Mac where the selection of potential supported hardware is even more tricky. The rest should work, but I'll leave it to the Mac people to comment on the mess that OSX is these days...
As Mylenium says, AE uses the GPU for very little natively: GPU (CUDA, OpenGL) features in After Effects CS6 and After Effects CC
And the ray-traced renderer is considered obsolete: http://motionworks.net/after-effects-3d-future/
So I wouldn't worry about that part at all.
Now, some third party plugins (Red Giant Universe, Video Copilot's Element 3d, Mettle's ShapeShifter, etc.) do use the GPU, but their requirements aren't tied to AE's at all, so again, no worries in After Effects.
Premiere, on the other hand, does use the GPU, so you should talk to the folks in the Premiere forum about that.
Thanks for getting back to me. That makes me feel beter I'm just learning
AF at the moment so it was bugging me.