I didn't notice them loosing charge over the short term. I hadn't used that body in over a year, so at that point they didn't have much charge left. I like that small rangefinder body style for travel.
I may still purchase a new Sony body for 4K video and travel next year. My GH4 does great for 4K video, but I like the APS C for photos, and the Sony body is much more compact.