the canon 70d is actually pretty bad for video, with terrible moire and mooshy video, the only good thing going for it is the decent aufocus in liveview.
I´m sorry but the olympus camera is far from being the best camera for video from that lot, a camera like the samsung nx1 or the sony a7rII or the best mirrorless camera for video is prob the sony a7IIs but certainly not the olympus.