Why on earth should one pay so much more for the E-P3, when there exists a virtually identical camera which costs so much less?
Because of the build quality, the form factor and the extra dial on the back . . . it's bigger though, and doesn't have the articulating screen.
The build quality is about the same, the form factor is a matter of taste, the extra dial isn't anything which is expensive. There is only the touch screen, which is a significantly better and pricier implementation than that of the Panasonic G3, and the flash which add something of substance. And there are some differences regarding the software. There are some features of the E-P3 which I would like to have, but I think that the price difference still seems to be bigger than the differences between both cameras suggest.