I never thought I'd have much use for a standard zoom. The focal range is nearly useless for most of the work I do, and when I am in that focal range I am usually using the ZD 50mm F/2, which is an AMAZING lens and I have no reason to replace it.
In any case, the 14-42 kit lens on the E510 is a sharp, light lens but it has a few flaws that make it a paperweight for me; It is too slow and doesn't provide enough magnification. F/3.5-5.6 just doesn't cut it for indoor ambient light shots, and a wide lens needs to focus close enough to the subject to distort perspective. I guess that's just a journalistic approach to shooting wide, but I think that getting right into the action makes wide angle shots less snapshotlike and more inclusive of the audience. A good wide angle shot needs to have a 3D quality to it, and sometimes that means getting VERY close. The added sharpness certainly won't hurt either, since it will likely see the most duty as a snake-in-habitat landscape lens.
The 14-42 is actually a very sharp lens, I didn't really have any issues with its performance there.
So, I went to buy the ZD 70-300 at calumet the other day, and of course they were out of stock. Seems every time I go there, they only have my second choice. Instead of the 70-300 I bought the 14-54.
The 50 F/2, 14-54 and the 70-300 will be my stable until I strike the lottery, so it was a planned purchase anyway. The only other option might have been the sigma 150 macro, but they don't carry sigma 4/3 lenses.
Compared to the 14-42, the 14-54 is a behemoth. It is probably twice as long, weighs at least five times as much, and is built like a tank. It is even heavier than the substantial 50 f/2, because of the more complicated build. I am struggling with this point, because I think that the small size and weight of the olympus kit lens is a huge asset. On the other hand, it is extremely solid and has a very good feel to it. I still might like a smaller, lighter lens with the same build quality, even if it meant sacrificing a few mm off the long end. Although pretty solidly built, the 14-42 has the same cheap feeling that the canon 50/1.8 has.
As far as image quality goes, the 14-54 is a head and shoulders above the 14-42. Having only fired a hundred or so frames with it, I am still finding out how it will be useful to me, but I can see that the bokeh is much improved, and the extra speed and performance is much appreciated. Sharpness seems great, and contrast and color are great also. There is something about the way an image looks when it is shot with good glass that is not quantifyable - something about the way the in-focus parts look, and the out of focus parts. This lens definitely exhibits that look.
The 14-54 also focuses quite closely - I think this lens will make a fine field lens for me, although honestly the wide end is more important than the long end. I'm not sure I'll use this lens much at the long end when I have the 50/f2 at my disposal. It will make a nice general purpose lens, for when a lens change is not really necessary, and it will make a fine ambient light indoor lens. More as I shoot more with it.