The 14-42mm II comes in a tiny box that already gives an idea how small the lens. In fact, it is much shorter and thinner than the 14-45mm; easier it is. The bayonet is - as it should be - made of metal. The housing itself is priced common plastic, the rear portion is covered with a thin aluminum, making it better visually noble. In general, the 14-42mm II affects quality than the 14-45mm, even if it is not actually (if only because "Made in China" vs. "Made in Japan").
A true masterpiece is the zoom mechanism. No tube, the ever extends the Ranzoomen. Instead, the lens is shortest at 25mm. Turning the zoom to the left or right, the tube moves each of only a few millimeters, made really great. Zoom and focus ring run very clean and are well damped, so you can use them precisely and without jerking.
But most important is of course the image quality and even here there is nothing to complain about. Visually, the 14-42mm II is superior to 14-45mm in most areas. CA, vignetting and distortion (uncorrected) are lower, but not necessarily are worlds apart. Only at the sharpness of 14-45mm, it does not quite reach. In wide angle at maximum aperture the difference at 100% view is best visible. Here the 14-45mm has the lead. But the difference is so small that it is hardly practical relevance. Outweigh the benefits of 14-42mm II and of my 14-45mm I have now separated me.