I'm using a FZ-1 which using the 12X Zoom Lecia. Personally, I love the zoom with stabiliser. Anything above 5X Optical will be shaky without it resulting in image blurr. And it has F2.8 apeture which allows lareg amount of light in.
As any camera, there is pros & cons. too much to discuss here.
For more mind-bogging on FZ-10, try www.dpreview.com and goes to Panasonic forum with hundreds of posting onit. So u gonna spend hrs to go throught with it and decide yrself.