Wow, thanks for all the replies guys. Some good points made by both fans of Olympus and Panasonic.
I assume choosing the size of the aperture and choosing the focus range...basic things like that are very well implemented by both companies??
Setting aperture and shutter speed, choosing ISO and white balance, and auto or manual focus are indeed easy to do if you wish to use the camera that way. I use my GF3 in almost exclusively aperture priority mode, and have it set up to have rapid access via dial and button to aperture, shutter speed, and I have set up the Function button to control ISO. Focus will be handled by the camera or, you can choose manual + auto, or full manual, and focus via the lens ring.
There are some differences between the implementation of these things in both cameras, and you would really need to try them both to see which works for you better.
Some of you guys have mentioned older models but I always assume they have older sensors and just not as advance. The reviews on this website stated that the Olympus E-PM1 has most of the features as the more expensive E-P3 and E-PL3. But the Panasonic G and GH series have much better sensors and noise reduction...am I right?
Not quite... The G3 and the GH2 have different and more advanced sensors, (both with 16MP vs the orginal 12MP sensors) than the GF3 and the EPM1/EPL3/EP3. Earlier generations of Pansonics (G1, G2, GF1, GF2) and Olys used the original 12MP sensors, too. HOWEVER, that being said, the 12MP sensor in the current generation of GF3 and the EPM1/EPL3/EP3 cameras, even though it is based on the same 12MP original sensor, is MUCH less noisy at higher ISOs and has all around better performance than earlier generations of the same sensor in both Panny and Oly cameras.
One thing I'm still looking at is another lens...roughly a 50-150mm lens. Price is an important consideration.
Both Panasonic and Olympus make lenses in that range. The Olympus 40-150 is an excellent zoom and can be had for a good price if you look for sales. It, however does NOT have OIS, so it is a little trickier to use on the long end on the Panasonic bodies. The Pansonic 45-200 does have OIS, but it is a lot bigger and heavier, and might be a bit awkward on either the GF3 or EPM1. The new Panny 45-175X model would be just right, except they still have not quite gotten the OIS on that lens working the way it should....
I think you could do ok with all of them (I have the Oly 40-150 and think it is a terrific lens, even on a my Panasonic camera bodies...it is probably the best bargain of all of this class of lens for M43s yet.)
-J