8 out of 10 points and recommendedgood value, decent optical performance, seems sturdyodd plastic, bit soft at f/2.8
As a replacement for a kit lens (even one that was as reasonable as Pentax's 18-55), this lens seems worthy of my investment. While I'm used to really sharp images through my elderly 50mm prime, changing from regular use of a kit lens (it being convenient and auto-focus) was an eye opening experience.reviewed February 15th, 2009 (purchased for $300)
This said, it is soft at f/2.8, not very badly, but enough that stopping down is usually in order. Of course, stopping down from f/2.8 still gives you more leeway than stopping down from f/4 or f/5.6. I have found though that f/8 is more like it for really sharp images (but this isn't unexpected judging by reviews of many lenses of this ilk). In all, a minor criticism really.
The lens seems well constructed, not a fabulous all metal affair, but nothing to complain about except the very strange texture, which is erm, shark-skin like? Difficult to explain, but its not going to stay pristine from the moment you put the lens on your camera.
While this is no replacement for a really good prime, I don't think anyone would suggest that it should be; but it covers a very useful range, and I have found it to be an excellent portrait lens, as it allows you to cover the important range (with the sensor crop) of about 70-100mm.
While sales literature will describe this as a lightweight and compact lens, that's only compared to a huge-range zoom I think, its much bigger and heavier than a kit lens (think bigger more expensive filters...). That said, the payoff for that weight is detailed above. If you want a really light lens, and you use Pentax, apparently their pancake lenses are excellent (though I've never had the chance to try one).
Overall, for the price, any minor complaints I've written here are pretty much moot - plus, dare I say it, having a wide barrel and a gold band, it makes you look like a big shot photographer :) Not that any of us would be so concerned about our image, only those which we produce!