Skepticism was certainly present. Especially with batteries of third-party I'm careful with my Panasonic cameras. The obscure Panasonic Firmware is well known in the scene. Here the use of batteries from other manufacturers is governed by software, on some models only remains of the original battery. I too had the problem with my GF and GH models. Accessories Battery bashing par exelance.
Now the good news: The here-reviewed Weiss battery power in my TZ no problems. It fits wonderfully sick, is not too long (which on some models lead to fatigue fractures of the key mechanism), nor too short and is accepted by the camera without any ifs and buts. Probably brings my original no longer the full power because the White holds definitely longer. But that may well be after two years of use.
My conclusion: Serious appearance, strong performance and a price that is bearable for what is offered.