14-45mm clearly outperforms the 14-42mm kit in terms of build and smoothness. My 14-42 has a harsh/sticky cheap zoom to the touch. The 14-45mm doesn't feel at all like a kit lens (which it used to be) and is clearly superior in design and performance. A recent 14-42 ride on the back of a GX1 on a fairly cold day was a little disappointing. Handling the camera and using the hard zoom ring was awkward. Even on a tripod, it was two-handed operation. Visually, everything is much closer. With 12 elements in 9 groups versus 9 elements in 8 groups, you would expect superior performance from the 14-45, which I think offers a few key areas for me. Both have 7 aperture blades, but I see softer bokeh (out of focus areas) at 14-45mm than at 14-42mm. But this, like the other optical characteristics mentioned, varies from negligible to barely noticeable (with the exception of distortion and sharpness at the edges/corners on some settings). This speaks very well for the quality of the optics of the 14-42mm lens. Both are about equally very sharp in the center and I would say looking at my images would be quite difficult to tell them apart. 14-45 gains edge sharpness, noticeable at some apertures. In both cases there is some vignetting at around 14mm, but stopping down to the sharpest lens openings (5.6-8) helped a lot in each case. I think 14-45 is much better at handling and controlling highlights and contrast, but that doesn't mean 14-42 is bad. The biggest optical advantage I see in a 14-45mm lens is the low distortion it produces. I was quite surprised by that. 14-42 isn't too bad here either, but at either end of the zoom range the distortion looks very strange (almost like a weird pincushion) and I had some images that were very difficult to correct. I think the 14-45mm is worth the extra money if you can find a new one. A clean used one is also worthwhile. If you're just starting out in the world of the M43, you'll need to ditch the body/lens kit and buy parts separately. The 14-45mm is slightly larger but I don't see that as a problem and again the smooth operation makes using these small cases that much more enjoyable.
New Nikon 18-105mm Vibration Reduction 📷 Zoom Lens with Auto Focus for Nikon DSLRs
104 Review
Canon EF 40mm f/2.8 STM Lens - Fixed Black (6310B002) for US Cameras
76 Review
Nikon 35mm f/1.8G Auto Focus Lens for Nikon DSLR Cameras - Black (Model 2183)
125 Review
Black Canon EF 24-105mm f/4L IS II USM Lens - Model 1380C002
78 Review