These are by far the best third party batteries for my Panasonic GH4 I tried (and I have tried a few). Sometimes I wonder if they last as long as the original ones -- where the original ones have a slighter edge though is the metering of the charge remaining. Yet for this price this is incredible buy, highly recommended.
They work as they should and seem no different at all to the battery that came with the camera. I have used this make on a Panasonic GM1 and GX7 successfully and now add the GH4 to the list. They feel exactly the same and there are no issues charging or using. Their life seems identical and they are a fraction of the price of the Panasonic ones !