Hmm. My 14-42 is with my son right now, but it has the metal mount. I got it with my Oly EP-2.
I use the lens, but it often leaves me wanting more. Its just not fair to compare the 14-42 to my other m43 lenses, and especially to lenses adapted to the EP-2. For me, distortion is not an issue with the lens. CA is kind of bad, but easily managed in Lightroom, Resolution is just not satisfying most of the time....a little soft at every FL and aperture. BUT, that's me looking at the images in the same session as images shot with Leica and Zeiss primes. I know that my son doesn't seem to have any problem with the performance of the 14-42.
Raid, because you have lenses that perform well, you may notice the limitations of the 14-42 as well.