So I ordered from Panasonic a second battery and the charger addition Baxxtar RAZER 600. And I'm absolutely happy with it. I have four different connectors to power the charger with power. In addition to micro-USB (mobile standard), USB and normal tabs for the normal 240 V power grid is also a car cigarette lighter adapter.
Recharging is quick and swiftly vonstatten, but I have this no comparative figures, especially since I never do the batteries completely empty.
The trick is that I can use the USB port as output and so recharge other devices or with electricity. So the phone is also loaded in the same car. And at home is one less cable to the desk ;-)
The build quality is top, it wobbles nothing and the RAZER makes a stable impression, although it is quite easy and so loosely fits with in the storage bag for your camcorder. It is slightly warm during charging, but this is probably the battery and is absolutely fine.
Incidentally, you should definitely remember to attach the included AC shell before commissioning. I have not seen the first, and tried in vain to insert the battery - which, of course not. I first thought of a wrong delivery for another model, until I have found the shell in the package. The can then simply slide and then budge.
From my side, strong buy recommendation!