12 questions on the Olympus OM-D/ Lumix GH3 - before I take the 4/3 plunge

Since you are into macro then the OM-D and the Zuiko  60mm macro lens is exceptional.   Even the 12-50 kit lens has a macro setting and can take very nice shots.  Look at sample images.   If you are into video mostly then go the GH3.  I think the OM-D is still the best for stills but from what I've seen the GH3 is pretty close.  The OM-D is small and takes getting use to.