If you read multiple reviews from different sources and used the camera
in the store you would find out that the FZ7 focus is much faster, the
usable features are richer even though the S3 has more features but many
are fluff and the ergonomics, menu configuration, size and weight and
street price are better.  Additionally you get the lens hood included.

Panasonic make a range of cameras, of excellent quality.  They have some
of the best lenses available (their Leica lenses perform measurably better
than their Canon equivalents).  I have had the Panasonic FZ5, and my wife
the Panasonic FZ20 for well over a year now and we would have no
hesitation in recommending them.

The Panasonic designs tend to have fewer gimmicks than the Canon, and use
standard memory cards (unlike the Sony).  Both Panasonic and Canon have a
longer history with image stabilised lenses than Sony at this level.

For me, the extra weight of the Sony [554g] or Canon [501g] compared to
the Panasonic FZ5 [326g] would be a drawback.

But look at the images, and try handling the cameras for yourself (I
rejected the earlier Canon S2 after handling tests).  You probably won't
be disappointed whichever you buy.

David