How does one answer that question? It really depends on your needs.

I needed a light-weight, compact, take anywhere, anytime, high
performance camera. The FZ5 is near perfect for my needs.

The FZ20 is an impressive camera, but is larger and has the older image
processing engine (slower, noisier). If you need manual focus and/or
hot shoe and don't mind the larger chassis, then the FZ20 is your
ticket.

For me, I love the FZ5 and have no regrets. I take it with me at times
that a larger camera would be left at home. It is light and small
enough to forget while I am carrying it around. At a recent school
function a couple of parents brought along their SLR cameras. I noticed
both of them had to keep one hand on the camera, (to keep it from
swinging and taking a load off their neck), while they were walking
around. It just plain looked uncomfortable.

I recently posted a review at amazon.com. Please check it and the
others out for more user input on the Panasonic DMC-FZ5.

I would love to see Panasonic morph the FZ20 into a higher quality
prosumer camera, like the Olympus C8080. Bring the size down a bit,
upgrade the processing engine, reduce the noise a bit at high ISO, and
wrap the whole thing in a sweet magnesium chassis.

So far, the FZ5 is performing beyond my expectations.

Good luck, TR

A better question would be, "How do these cameras differ and
which differences are most immportant to me?"

The FZ20 is bulkier both in size and weight.

The FZ20 has a flash hot-shoe.

The FZ20 has an ED element in the lens, so it might have
better sharpness under some circumstances.  I don't think
I've seen a good analysis of this on any of the review
sites.

The FZ20 has a very nice ring-operated fly-by-wire manual
focus, while the FZ5 has no manual focus.  People are saying
this doesn't really matter.  Both cameras appear to have
some sort of multi-zone autofocus scheme.  If you can force
the camera to focus on a particular zone, that would be
almost as good as a real manual focus.  The manuals are
unclear and I have not seen any owner of one of these
cameras describe how the multi-zone focus actually works.

It looks as if it might be simpler to adapt filters to
the FZ20 than to the FZ5, but this may be just because the
FZ5 has not been around as long.  I'm to the point where
I know I want to use ND and polarizing filters for some
shots, so this is important to me.

The FZ5 is a little less expensive.

My current camera is an Olympus C700UZ.  Either of the FZ5
or the FZ20 would be a nice upgrade.  I'd rather have the
smaller camera, but I'm held back over not knowing how the
autofocus works and not knowing exactly what the lens
tradeoff is.

Paul Allen

Not either one.  The FZ5 is more general consumer oriented.

Objectively? FZ20. Subjectively? You might find the FZ5 suits your needs
and your budget, in which case why spend more?

pete

Has anyone yet seen a published portrait taken with either the FZ5 or FZ20
showing natural skin tones, and not overly pink, red or orange?
Check out this pic:
http://img2.dpreview.com/gallery/panasonicfz20_samples/040919-1100-10.jpg
The sitting guy has the typical FZ style red face, but the girl on the
poster has a much more subtle face color.
Is it that the camera overreacts from the natural haemoglobin of people but
not from printed colors?

/per