I have had the Olympus Pen-F since it was released but just picked up the Panasonic 12-60 to see if I like it as a walk-around/travel lens. So far the impressions (after just getting it) are very good. Nice and light - balances well with the Pen-F. AF was very quick - even in some dimly lit indoor shots. Color and contrast on the Olympus body was - for me - very nice.