14mm is my most used focal length on MFT, so I bought the 14mm Pany even though I had that length covered by both the 7-14mm and the Oly 14-42mm kit zoom. My testing shows that the little prime is somewhat softer in the corners at all common apertures than the Oly kit zoom. My results are contrary to the Imatest results published on the Lensrental blog, which showed the 14mm to be among the sharpest lenses tested and the Oly 14-42 to be below average, but they are in line with the results from SLRGear. I don't have any experience with the 12mm, but it's way too expensive for a focal length that I already have. I may keep the 14mm to have a 3-prime kit (14, 20, 45), but I don't see that it provides much real advantage over the kit zoom.