Quite debatable that the Olympus 14-54 is better. On the contrary...I have read many reviews where the Pana/Leica is considered the better. The Pana/Leica is clearer and brighter wide open and does not vignette at the corners like the Olympus. Also the Pana/Leica is sharp across the entire image without softening at the corners like the Olympus 14-54. Also the bokeh is a lot more pleasing with the Pana/Leica.
14-54 MkII is sharper wide-open, with less distortion, less CA. It is also built better (or at least feels better), has weatherproof, is smaller and incorporates smaller filter thread. Its max. magnification is better and zoom ring has the "proper" direction. PL was much better in terms of bokeh compared to MkI, but MkII is close as its bokeh rendition is definitely improved. PL also tends to fail quite often, which doesn't seems to be case of 14-54 MkII. Based on my experience Zuiko is better hands-down regardless on price, but for the half it is a steal.
I have used 14-54 MkI for years, 12-60 for one year, 14-50 for less than one year and 14-54 MkII just for one week, found MkII best of the bunch.
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