For a static scene, is there any visual difference between Baked and Realtime GI?

I understand the performance advantages of using a fulled baked lighting pipeline, but, if all other settings are equal, in a static scene should there be any visual difference between using
a)Baked GI
and
b)Precomputed Realtime GI

Also, is there any reason why you might have BOTH options selected in your Lighting preferences?

Both are calculated differently so they will have a slightly different style. (A) will give you tight detailed shadows. You will also get tighter light transitions. (A) can also give you nice clean baked AO if you want that. The texture memory required for Realtime GI seems to be lower (unconfirmed) and its inherently dynamic.