Battery life is good, should give around 90 minutes of recording, which will fill one 64Gb card when recording 4k. Worth investing in a few spare batteries and cards if you are on a trip. I’ve never shot handheld and therefore I always have the stabiliser turned off.
Sorry for the late reply. I cover the camera mic with an off cut of fake fur. But the camera can still pick up wind noise if its windy, so I also use a Rode stereo mic plugged in to Sony voice recorder. I keep hoping that Panasonic will bring out a new version with a mic socket and a flip out LCD screen.