After playing with both cameras, I came away mighty impressed with the E-P3 which has addressed most of the issues I had with the original E-P1, namely the difficult manual focus, lack of a dedicated zoom LCD button and AF button (although the latter can be configured to one of the others). The AF speed is also greatly enhanced and the addition of a low-light AF assist works wonders. The repositioning of the on/off switch is much improved but would have been better as a rotating ring around the shutter button common on many cameras.
I was so impressed that I bought the E-P3 and the kit zoom on the night. The following photos was taken with the E-P3 and my Voigtlander 25mm f/0.95 lens and was taken pre-dawn in reasonably foggy conditions. It was a "warm" 1 degrees that morning.
I did struggle a little with the processing having to use Olympus Viewer 2 to do the RAW conversion and I know I will be able to get a better result when Adobe comes good with support in Adobe Camera RAW. Cannot wait.
I have to say that what was once a slightly difficult lens to get focused is now brilliant. The extra resolution of the LCD combined with its great brightness and dedicated LCD zoom - well just sweet. It is nice to be able to see an image on an LCD with next to no light.
Now I did mention the E-PL3 - I went away unimpressed by that camera. I found the menus less useful and missed the extra direct controls. Yes, I would have loved a fold out LCD but the E-P3 does a better job of the compromise and feels a much nicer camera to hold. I think the E-PL3 would be fine if you do mostly auto shooting but I do mostly manual shooting.
About the only area where the E-P3 takes a tiny step backward is with ISO. The high ISO and low light ISO performance is definitely better but why did they drop ISO100. I use that for long exposure shots at dawn and also for studio portrait work under studio lights otherwise I have to stop down more than I want to. I guess I will be using 1 and 2 stop NDs more often.
As well as the cameras I played with the new Olympus lenses. Wow - the 12mm f/2 and its mechanical manual focus ring is superb as is the quality metal construction. It isn't available until the end of August in Australia but I have placed my order. It won't be cheap but I have paid more for lenses.
The 45mm f/1.8 is a fairly standard bit of kit and less than half the price of the 12mm. It seems good value for the money and I will probably get one eventually when I have a bit more portrait stuff to do but somehow I just didn't get excited about it.
In a nutshell, the E-P3 is a lovely camera and a great update on my E-P1.