So, um, what are the differences between these two?

I can't seem to find my answer by searching other than "in omega ruby magma are the bad guys you fight," and "in alpha sapphire aqua are the bad guys you fight."

Basically, I'm just asking what are the big changes between them. I know there is a pokemon difference; is it the same as the originals?

I'm not sure if I'm going to buy it now, so that way it comes on release. Or if I'll wait a bit and pick it up.