Don't get the FZ3, if anything get the fz20. however, depending where you are that could be a significant increase in price.
Personally, I like the canon menu system alot. But thats due to having owned canon in the past. One thing I don't like about panasonics, is their menu system my panasonic camcoreder has a horrible menu system and I have to open the LCD to make any changes to it (sorry just ranting).
There are other little things like being able to turn OIS off with one button on S1 vs going through menu to sdo it.
Also, consider that the lcd of most of the cameras aswell as being a small 1.5" don't rotate. one thing I can tell you about wedding pics is often your hand is above your head trying to get a shot in the mass confusion. you definetly want a twist out Lcd for this purpose. I mean, its not like your gonna have the access the wedding photographer has. And AA batteries are a god send for ocasions like this where you'll be firing your flash to the wee hours of the night!