I haven't used my ZS3 much, but I quickly found out a few things.
1) The flash range is very limited. In my experience, you need to be no more than about five or six feet from your subject (at full wide-angle setting) to get a good exposure.
2) If you have your lens zoomed all the way out (300mm), unless you're outdoors under bright skies, you'd better use a tripod ... or at least have something to lean on. The slightest shake of the camera will cause a blurry picture (yes, even with image stabilization). So, if you're taking pictures of kids in a play and you're zoomed all the way out, be sure the camera is braced on something sturdy.
Note: My comments are based upon ISO 80 -- which is what I try to use 95% of the time for the best image quality.
--StevenN