In reply to ROB W:
> ... in the alps for sevreal days at a time,so charging can be a bit of pain,or exstended trips in greater ranges,
Forget charging unless it's a really long lightweight trip and just buy several generic spares. Cheaper, lighter, less faff. You should get at least 250 shots per battery in general use, but lots of video, zooming and cold will affect that.
The Panasonic 14-42 compact powerzoom looks great but got terrible reviews and has not been popular. It would have made a great climbing rig on the G3/G5.