DxOmark (Click here) posted the E-Pl3 and E-PM1 sensors test results. As usual keep in mind that these tests do not take into consoderation the resolution of the sensor. DxO says: “Even if these 2 new models in the PEN series don’t provide any improvement in image quality, they do offer new choices in terms of size and controls. Depending on the level of control you want, these 2 cameras could be very nice point-and-shoot cameras — portable, but with interchangeable lenses“.
As you know all three latest PEN models do use the same 12 megapixel sensor. It’s up to you whihc one fits better for you!