This is going to be a recurring question, so I'll post my take home summary here, having used the Panasonic Leica 25mm f/1.4 (PL25) and Olympus 25mm f/1.8 (O25) these past couple weeks. Napier also posted his take. In favor of the O25: -Smaller (especially if you include hoods; also, only the O25 hood reverses for storage) -Lighter -Lower price -Closer minimum focus distance -Less color fringing in general including bokeh color fringing (though keep in mind that Pana bodies will effectively eliminate lateral CA on the PL lens) -More evenly sharp across the frame, in large part because there is less optical distortion needing software correction -Doesn't ever "rattlesnake" (PL25 can have an aperture blade chattering sound occasionally on Oly bodies, though to me this is rare) -Slightly faster focusing (both focus quickly) In favor of the PL25: -2/3 stop faster -Noticeably more shallow DOF with close subjects and distant backgrounds -Better flare resistance -Slightly smoother bokeh at matched f-stops -Build feels more robust (to me) Other differences: -O25 is a bit wider but the difference in angle of view is negligible with distant subjects (the difference with close subjects seems to be largely a result of focus breathing) Bottom line (for me): -Both are great normal lenses. The size/weight difference is only significant to me when using the smallest MFT cameras (eg, E-PM2, GM1). I was thinking I'd sell one or the other, but it looks like I'll be keeping both for now.