The Panasonic IBIS is very impressive and from the examples I've seen is on par with the current Olympus E-M1. But Olympus are promising 6.5stops in the MKii - which is insane.
Still think, in the end the GH5 will be massively better for video use, but lots of choices inbound. Alas BHPhoto have stated the GH5 isn't due to NEXT summer. Bummer..