I have a FZ15 and don't think it's slow to focus. I have not taken a stopwatch to it but I would think it is under a second. I did notice that under low light, it takes a little longer than in the day light. Would I call it slow? No, not at all. If you look at Steve review of the FZ15, I think he has some shutter delay times in that review.
Here is the link to the page with that information on it
I don't think a camera can be to slow to take a pic like this:G