I get maximum image quality bang for my bucks when I use single focal length lenses on my Panasonic and Olympus cameras but there are times when you're walking through a crowd and you want to shoot instantly. But you have the wrong lens on the camera and by the time you get into your bag and get the lens changed out the image you were lusting after is long gone. In those situations it makes sense to use a zoom lens. Panasonic and Olympus make a bunch of "normal" zoom lenses. Most of the cameras come with one in the "kit."
I've got a collection of them. Lately, when I get them in kits, I try to trade them for pricey, name brand camera batteries. But I also wanted a good one so I did my research on the various web sites that do lens test (Photozone, SLRgear) and decided to try the grandfather of m4:3 zooms, the Panasonic you see above. It's small and light but a little bigger than the current Panasonic 14-42. The newer lens doesn't have the Optical Image Stabilization switch on the body. The older one does (see above).
I decided I needed a better lens when I tested the 14-42 that came with my G3. It was consistently soft at the long end and got worse as I focused to infinity. What did I have to lose? I waited until one of those days when Amazon.com's dynamic pricing algorithm was in my favor and bought one for around $225. Long story compressed to digestible tidbit? It's good. The center is really nice and sharp and stays that way from wide to tele. It's sharp wide open (in the center 2/3rds of the frame) and that's where I like to use it. I spent an afternoon shooting with it on the GH2 body and it's a revelation how much fun it is to shoot with a small and light camera and lens package.